1461 lines
52 KiB
Python
1461 lines
52 KiB
Python
from sympy.calculus.accumulationbounds import AccumBounds
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from sympy.core.function import (expand_mul, expand_trig)
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from sympy.core.numbers import (E, I, Integer, Rational, nan, oo, pi, zoo)
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from sympy.core.singleton import S
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from sympy.core.symbol import (Symbol, symbols)
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from sympy.functions.elementary.complexes import (im, re)
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from sympy.functions.elementary.exponential import (exp, log)
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from sympy.functions.elementary.hyperbolic import (acosh, acoth, acsch, asech, asinh, atanh, cosh, coth, csch, sech, sinh, tanh)
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from sympy.functions.elementary.miscellaneous import sqrt
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from sympy.functions.elementary.trigonometric import (acos, asin, cos, cot, sec, sin, tan)
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from sympy.series.order import O
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from sympy.core.expr import unchanged
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from sympy.core.function import ArgumentIndexError
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from sympy.testing.pytest import raises
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def test_sinh():
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x, y = symbols('x,y')
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k = Symbol('k', integer=True)
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assert sinh(nan) is nan
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assert sinh(zoo) is nan
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assert sinh(oo) is oo
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assert sinh(-oo) is -oo
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assert sinh(0) == 0
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assert unchanged(sinh, 1)
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assert sinh(-1) == -sinh(1)
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assert unchanged(sinh, x)
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assert sinh(-x) == -sinh(x)
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assert unchanged(sinh, pi)
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assert sinh(-pi) == -sinh(pi)
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assert unchanged(sinh, 2**1024 * E)
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assert sinh(-2**1024 * E) == -sinh(2**1024 * E)
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assert sinh(pi*I) == 0
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assert sinh(-pi*I) == 0
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assert sinh(2*pi*I) == 0
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assert sinh(-2*pi*I) == 0
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assert sinh(-3*10**73*pi*I) == 0
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assert sinh(7*10**103*pi*I) == 0
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assert sinh(pi*I/2) == I
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assert sinh(-pi*I/2) == -I
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assert sinh(pi*I*Rational(5, 2)) == I
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assert sinh(pi*I*Rational(7, 2)) == -I
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assert sinh(pi*I/3) == S.Half*sqrt(3)*I
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assert sinh(pi*I*Rational(-2, 3)) == Rational(-1, 2)*sqrt(3)*I
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assert sinh(pi*I/4) == S.Half*sqrt(2)*I
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assert sinh(-pi*I/4) == Rational(-1, 2)*sqrt(2)*I
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assert sinh(pi*I*Rational(17, 4)) == S.Half*sqrt(2)*I
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assert sinh(pi*I*Rational(-3, 4)) == Rational(-1, 2)*sqrt(2)*I
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assert sinh(pi*I/6) == S.Half*I
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assert sinh(-pi*I/6) == Rational(-1, 2)*I
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assert sinh(pi*I*Rational(7, 6)) == Rational(-1, 2)*I
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assert sinh(pi*I*Rational(-5, 6)) == Rational(-1, 2)*I
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assert sinh(pi*I/105) == sin(pi/105)*I
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assert sinh(-pi*I/105) == -sin(pi/105)*I
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assert unchanged(sinh, 2 + 3*I)
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assert sinh(x*I) == sin(x)*I
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assert sinh(k*pi*I) == 0
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assert sinh(17*k*pi*I) == 0
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assert sinh(k*pi*I/2) == sin(k*pi/2)*I
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assert sinh(x).as_real_imag(deep=False) == (cos(im(x))*sinh(re(x)),
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sin(im(x))*cosh(re(x)))
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x = Symbol('x', extended_real=True)
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assert sinh(x).as_real_imag(deep=False) == (sinh(x), 0)
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x = Symbol('x', real=True)
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assert sinh(I*x).is_finite is True
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assert sinh(x).is_real is True
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assert sinh(I).is_real is False
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p = Symbol('p', positive=True)
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assert sinh(p).is_zero is False
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assert sinh(0, evaluate=False).is_zero is True
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assert sinh(2*pi*I, evaluate=False).is_zero is True
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def test_sinh_series():
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x = Symbol('x')
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assert sinh(x).series(x, 0, 10) == \
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x + x**3/6 + x**5/120 + x**7/5040 + x**9/362880 + O(x**10)
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def test_sinh_fdiff():
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x = Symbol('x')
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raises(ArgumentIndexError, lambda: sinh(x).fdiff(2))
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def test_cosh():
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x, y = symbols('x,y')
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k = Symbol('k', integer=True)
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assert cosh(nan) is nan
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assert cosh(zoo) is nan
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assert cosh(oo) is oo
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assert cosh(-oo) is oo
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assert cosh(0) == 1
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assert unchanged(cosh, 1)
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assert cosh(-1) == cosh(1)
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assert unchanged(cosh, x)
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assert cosh(-x) == cosh(x)
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assert cosh(pi*I) == cos(pi)
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assert cosh(-pi*I) == cos(pi)
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assert unchanged(cosh, 2**1024 * E)
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assert cosh(-2**1024 * E) == cosh(2**1024 * E)
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assert cosh(pi*I/2) == 0
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assert cosh(-pi*I/2) == 0
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assert cosh((-3*10**73 + 1)*pi*I/2) == 0
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assert cosh((7*10**103 + 1)*pi*I/2) == 0
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assert cosh(pi*I) == -1
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assert cosh(-pi*I) == -1
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assert cosh(5*pi*I) == -1
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assert cosh(8*pi*I) == 1
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assert cosh(pi*I/3) == S.Half
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assert cosh(pi*I*Rational(-2, 3)) == Rational(-1, 2)
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assert cosh(pi*I/4) == S.Half*sqrt(2)
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assert cosh(-pi*I/4) == S.Half*sqrt(2)
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assert cosh(pi*I*Rational(11, 4)) == Rational(-1, 2)*sqrt(2)
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assert cosh(pi*I*Rational(-3, 4)) == Rational(-1, 2)*sqrt(2)
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assert cosh(pi*I/6) == S.Half*sqrt(3)
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assert cosh(-pi*I/6) == S.Half*sqrt(3)
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assert cosh(pi*I*Rational(7, 6)) == Rational(-1, 2)*sqrt(3)
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assert cosh(pi*I*Rational(-5, 6)) == Rational(-1, 2)*sqrt(3)
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assert cosh(pi*I/105) == cos(pi/105)
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assert cosh(-pi*I/105) == cos(pi/105)
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assert unchanged(cosh, 2 + 3*I)
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assert cosh(x*I) == cos(x)
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assert cosh(k*pi*I) == cos(k*pi)
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assert cosh(17*k*pi*I) == cos(17*k*pi)
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assert unchanged(cosh, k*pi)
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assert cosh(x).as_real_imag(deep=False) == (cos(im(x))*cosh(re(x)),
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sin(im(x))*sinh(re(x)))
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x = Symbol('x', extended_real=True)
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assert cosh(x).as_real_imag(deep=False) == (cosh(x), 0)
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x = Symbol('x', real=True)
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assert cosh(I*x).is_finite is True
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assert cosh(I*x).is_real is True
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assert cosh(I*2 + 1).is_real is False
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assert cosh(5*I*S.Pi/2, evaluate=False).is_zero is True
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assert cosh(x).is_zero is False
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def test_cosh_series():
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x = Symbol('x')
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assert cosh(x).series(x, 0, 10) == \
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1 + x**2/2 + x**4/24 + x**6/720 + x**8/40320 + O(x**10)
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def test_cosh_fdiff():
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x = Symbol('x')
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raises(ArgumentIndexError, lambda: cosh(x).fdiff(2))
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def test_tanh():
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x, y = symbols('x,y')
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k = Symbol('k', integer=True)
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assert tanh(nan) is nan
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assert tanh(zoo) is nan
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assert tanh(oo) == 1
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assert tanh(-oo) == -1
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assert tanh(0) == 0
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assert unchanged(tanh, 1)
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assert tanh(-1) == -tanh(1)
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assert unchanged(tanh, x)
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assert tanh(-x) == -tanh(x)
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assert unchanged(tanh, pi)
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assert tanh(-pi) == -tanh(pi)
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assert unchanged(tanh, 2**1024 * E)
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assert tanh(-2**1024 * E) == -tanh(2**1024 * E)
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assert tanh(pi*I) == 0
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assert tanh(-pi*I) == 0
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assert tanh(2*pi*I) == 0
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assert tanh(-2*pi*I) == 0
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assert tanh(-3*10**73*pi*I) == 0
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assert tanh(7*10**103*pi*I) == 0
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assert tanh(pi*I/2) is zoo
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assert tanh(-pi*I/2) is zoo
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assert tanh(pi*I*Rational(5, 2)) is zoo
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assert tanh(pi*I*Rational(7, 2)) is zoo
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assert tanh(pi*I/3) == sqrt(3)*I
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assert tanh(pi*I*Rational(-2, 3)) == sqrt(3)*I
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assert tanh(pi*I/4) == I
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assert tanh(-pi*I/4) == -I
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assert tanh(pi*I*Rational(17, 4)) == I
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assert tanh(pi*I*Rational(-3, 4)) == I
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assert tanh(pi*I/6) == I/sqrt(3)
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assert tanh(-pi*I/6) == -I/sqrt(3)
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assert tanh(pi*I*Rational(7, 6)) == I/sqrt(3)
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assert tanh(pi*I*Rational(-5, 6)) == I/sqrt(3)
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assert tanh(pi*I/105) == tan(pi/105)*I
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assert tanh(-pi*I/105) == -tan(pi/105)*I
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assert unchanged(tanh, 2 + 3*I)
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assert tanh(x*I) == tan(x)*I
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assert tanh(k*pi*I) == 0
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assert tanh(17*k*pi*I) == 0
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assert tanh(k*pi*I/2) == tan(k*pi/2)*I
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assert tanh(x).as_real_imag(deep=False) == (sinh(re(x))*cosh(re(x))/(cos(im(x))**2
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+ sinh(re(x))**2),
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sin(im(x))*cos(im(x))/(cos(im(x))**2 + sinh(re(x))**2))
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x = Symbol('x', extended_real=True)
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assert tanh(x).as_real_imag(deep=False) == (tanh(x), 0)
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assert tanh(I*pi/3 + 1).is_real is False
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assert tanh(x).is_real is True
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assert tanh(I*pi*x/2).is_real is None
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def test_tanh_series():
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x = Symbol('x')
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assert tanh(x).series(x, 0, 10) == \
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x - x**3/3 + 2*x**5/15 - 17*x**7/315 + 62*x**9/2835 + O(x**10)
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def test_tanh_fdiff():
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x = Symbol('x')
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raises(ArgumentIndexError, lambda: tanh(x).fdiff(2))
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def test_coth():
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x, y = symbols('x,y')
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k = Symbol('k', integer=True)
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assert coth(nan) is nan
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assert coth(zoo) is nan
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assert coth(oo) == 1
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assert coth(-oo) == -1
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assert coth(0) is zoo
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assert unchanged(coth, 1)
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assert coth(-1) == -coth(1)
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assert unchanged(coth, x)
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assert coth(-x) == -coth(x)
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assert coth(pi*I) == -I*cot(pi)
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assert coth(-pi*I) == cot(pi)*I
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assert unchanged(coth, 2**1024 * E)
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assert coth(-2**1024 * E) == -coth(2**1024 * E)
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assert coth(pi*I) == -I*cot(pi)
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assert coth(-pi*I) == I*cot(pi)
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assert coth(2*pi*I) == -I*cot(2*pi)
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assert coth(-2*pi*I) == I*cot(2*pi)
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assert coth(-3*10**73*pi*I) == I*cot(3*10**73*pi)
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assert coth(7*10**103*pi*I) == -I*cot(7*10**103*pi)
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assert coth(pi*I/2) == 0
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assert coth(-pi*I/2) == 0
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assert coth(pi*I*Rational(5, 2)) == 0
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assert coth(pi*I*Rational(7, 2)) == 0
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assert coth(pi*I/3) == -I/sqrt(3)
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assert coth(pi*I*Rational(-2, 3)) == -I/sqrt(3)
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assert coth(pi*I/4) == -I
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assert coth(-pi*I/4) == I
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assert coth(pi*I*Rational(17, 4)) == -I
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assert coth(pi*I*Rational(-3, 4)) == -I
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assert coth(pi*I/6) == -sqrt(3)*I
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assert coth(-pi*I/6) == sqrt(3)*I
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assert coth(pi*I*Rational(7, 6)) == -sqrt(3)*I
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assert coth(pi*I*Rational(-5, 6)) == -sqrt(3)*I
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assert coth(pi*I/105) == -cot(pi/105)*I
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assert coth(-pi*I/105) == cot(pi/105)*I
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assert unchanged(coth, 2 + 3*I)
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assert coth(x*I) == -cot(x)*I
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assert coth(k*pi*I) == -cot(k*pi)*I
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assert coth(17*k*pi*I) == -cot(17*k*pi)*I
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assert coth(k*pi*I) == -cot(k*pi)*I
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assert coth(log(tan(2))) == coth(log(-tan(2)))
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assert coth(1 + I*pi/2) == tanh(1)
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assert coth(x).as_real_imag(deep=False) == (sinh(re(x))*cosh(re(x))/(sin(im(x))**2
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+ sinh(re(x))**2),
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-sin(im(x))*cos(im(x))/(sin(im(x))**2 + sinh(re(x))**2))
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x = Symbol('x', extended_real=True)
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assert coth(x).as_real_imag(deep=False) == (coth(x), 0)
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assert expand_trig(coth(2*x)) == (coth(x)**2 + 1)/(2*coth(x))
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assert expand_trig(coth(3*x)) == (coth(x)**3 + 3*coth(x))/(1 + 3*coth(x)**2)
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assert expand_trig(coth(x + y)) == (1 + coth(x)*coth(y))/(coth(x) + coth(y))
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def test_coth_series():
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x = Symbol('x')
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assert coth(x).series(x, 0, 8) == \
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1/x + x/3 - x**3/45 + 2*x**5/945 - x**7/4725 + O(x**8)
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def test_coth_fdiff():
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x = Symbol('x')
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raises(ArgumentIndexError, lambda: coth(x).fdiff(2))
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def test_csch():
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x, y = symbols('x,y')
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k = Symbol('k', integer=True)
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n = Symbol('n', positive=True)
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assert csch(nan) is nan
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assert csch(zoo) is nan
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assert csch(oo) == 0
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assert csch(-oo) == 0
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assert csch(0) is zoo
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assert csch(-1) == -csch(1)
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assert csch(-x) == -csch(x)
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assert csch(-pi) == -csch(pi)
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assert csch(-2**1024 * E) == -csch(2**1024 * E)
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assert csch(pi*I) is zoo
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assert csch(-pi*I) is zoo
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assert csch(2*pi*I) is zoo
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assert csch(-2*pi*I) is zoo
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assert csch(-3*10**73*pi*I) is zoo
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assert csch(7*10**103*pi*I) is zoo
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assert csch(pi*I/2) == -I
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assert csch(-pi*I/2) == I
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assert csch(pi*I*Rational(5, 2)) == -I
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assert csch(pi*I*Rational(7, 2)) == I
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assert csch(pi*I/3) == -2/sqrt(3)*I
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assert csch(pi*I*Rational(-2, 3)) == 2/sqrt(3)*I
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assert csch(pi*I/4) == -sqrt(2)*I
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assert csch(-pi*I/4) == sqrt(2)*I
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assert csch(pi*I*Rational(7, 4)) == sqrt(2)*I
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assert csch(pi*I*Rational(-3, 4)) == sqrt(2)*I
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assert csch(pi*I/6) == -2*I
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assert csch(-pi*I/6) == 2*I
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assert csch(pi*I*Rational(7, 6)) == 2*I
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assert csch(pi*I*Rational(-7, 6)) == -2*I
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assert csch(pi*I*Rational(-5, 6)) == 2*I
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assert csch(pi*I/105) == -1/sin(pi/105)*I
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assert csch(-pi*I/105) == 1/sin(pi/105)*I
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assert csch(x*I) == -1/sin(x)*I
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assert csch(k*pi*I) is zoo
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assert csch(17*k*pi*I) is zoo
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assert csch(k*pi*I/2) == -1/sin(k*pi/2)*I
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assert csch(n).is_real is True
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assert expand_trig(csch(x + y)) == 1/(sinh(x)*cosh(y) + cosh(x)*sinh(y))
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def test_csch_series():
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x = Symbol('x')
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assert csch(x).series(x, 0, 10) == \
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1/ x - x/6 + 7*x**3/360 - 31*x**5/15120 + 127*x**7/604800 \
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- 73*x**9/3421440 + O(x**10)
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def test_csch_fdiff():
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x = Symbol('x')
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raises(ArgumentIndexError, lambda: csch(x).fdiff(2))
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def test_sech():
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x, y = symbols('x, y')
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k = Symbol('k', integer=True)
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n = Symbol('n', positive=True)
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assert sech(nan) is nan
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assert sech(zoo) is nan
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assert sech(oo) == 0
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assert sech(-oo) == 0
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assert sech(0) == 1
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assert sech(-1) == sech(1)
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assert sech(-x) == sech(x)
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assert sech(pi*I) == sec(pi)
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assert sech(-pi*I) == sec(pi)
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assert sech(-2**1024 * E) == sech(2**1024 * E)
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assert sech(pi*I/2) is zoo
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assert sech(-pi*I/2) is zoo
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|
assert sech((-3*10**73 + 1)*pi*I/2) is zoo
|
|
assert sech((7*10**103 + 1)*pi*I/2) is zoo
|
|
|
|
assert sech(pi*I) == -1
|
|
assert sech(-pi*I) == -1
|
|
assert sech(5*pi*I) == -1
|
|
assert sech(8*pi*I) == 1
|
|
|
|
assert sech(pi*I/3) == 2
|
|
assert sech(pi*I*Rational(-2, 3)) == -2
|
|
|
|
assert sech(pi*I/4) == sqrt(2)
|
|
assert sech(-pi*I/4) == sqrt(2)
|
|
assert sech(pi*I*Rational(5, 4)) == -sqrt(2)
|
|
assert sech(pi*I*Rational(-5, 4)) == -sqrt(2)
|
|
|
|
assert sech(pi*I/6) == 2/sqrt(3)
|
|
assert sech(-pi*I/6) == 2/sqrt(3)
|
|
assert sech(pi*I*Rational(7, 6)) == -2/sqrt(3)
|
|
assert sech(pi*I*Rational(-5, 6)) == -2/sqrt(3)
|
|
|
|
assert sech(pi*I/105) == 1/cos(pi/105)
|
|
assert sech(-pi*I/105) == 1/cos(pi/105)
|
|
|
|
assert sech(x*I) == 1/cos(x)
|
|
|
|
assert sech(k*pi*I) == 1/cos(k*pi)
|
|
assert sech(17*k*pi*I) == 1/cos(17*k*pi)
|
|
|
|
assert sech(n).is_real is True
|
|
|
|
assert expand_trig(sech(x + y)) == 1/(cosh(x)*cosh(y) + sinh(x)*sinh(y))
|
|
|
|
|
|
def test_sech_series():
|
|
x = Symbol('x')
|
|
assert sech(x).series(x, 0, 10) == \
|
|
1 - x**2/2 + 5*x**4/24 - 61*x**6/720 + 277*x**8/8064 + O(x**10)
|
|
|
|
|
|
def test_sech_fdiff():
|
|
x = Symbol('x')
|
|
raises(ArgumentIndexError, lambda: sech(x).fdiff(2))
|
|
|
|
|
|
def test_asinh():
|
|
x, y = symbols('x,y')
|
|
assert unchanged(asinh, x)
|
|
assert asinh(-x) == -asinh(x)
|
|
|
|
#at specific points
|
|
assert asinh(nan) is nan
|
|
assert asinh( 0) == 0
|
|
assert asinh(+1) == log(sqrt(2) + 1)
|
|
|
|
assert asinh(-1) == log(sqrt(2) - 1)
|
|
assert asinh(I) == pi*I/2
|
|
assert asinh(-I) == -pi*I/2
|
|
assert asinh(I/2) == pi*I/6
|
|
assert asinh(-I/2) == -pi*I/6
|
|
|
|
# at infinites
|
|
assert asinh(oo) is oo
|
|
assert asinh(-oo) is -oo
|
|
|
|
assert asinh(I*oo) is oo
|
|
assert asinh(-I *oo) is -oo
|
|
|
|
assert asinh(zoo) is zoo
|
|
|
|
#properties
|
|
assert asinh(I *(sqrt(3) - 1)/(2**Rational(3, 2))) == pi*I/12
|
|
assert asinh(-I *(sqrt(3) - 1)/(2**Rational(3, 2))) == -pi*I/12
|
|
|
|
assert asinh(I*(sqrt(5) - 1)/4) == pi*I/10
|
|
assert asinh(-I*(sqrt(5) - 1)/4) == -pi*I/10
|
|
|
|
assert asinh(I*(sqrt(5) + 1)/4) == pi*I*Rational(3, 10)
|
|
assert asinh(-I*(sqrt(5) + 1)/4) == pi*I*Rational(-3, 10)
|
|
|
|
# Symmetry
|
|
assert asinh(Rational(-1, 2)) == -asinh(S.Half)
|
|
|
|
# inverse composition
|
|
assert unchanged(asinh, sinh(Symbol('v1')))
|
|
|
|
assert asinh(sinh(0, evaluate=False)) == 0
|
|
assert asinh(sinh(-3, evaluate=False)) == -3
|
|
assert asinh(sinh(2, evaluate=False)) == 2
|
|
assert asinh(sinh(I, evaluate=False)) == I
|
|
assert asinh(sinh(-I, evaluate=False)) == -I
|
|
assert asinh(sinh(5*I, evaluate=False)) == -2*I*pi + 5*I
|
|
assert asinh(sinh(15 + 11*I)) == 15 - 4*I*pi + 11*I
|
|
assert asinh(sinh(-73 + 97*I)) == 73 - 97*I + 31*I*pi
|
|
assert asinh(sinh(-7 - 23*I)) == 7 - 7*I*pi + 23*I
|
|
assert asinh(sinh(13 - 3*I)) == -13 - I*pi + 3*I
|
|
p = Symbol('p', positive=True)
|
|
assert asinh(p).is_zero is False
|
|
assert asinh(sinh(0, evaluate=False), evaluate=False).is_zero is True
|
|
|
|
|
|
def test_asinh_rewrite():
|
|
x = Symbol('x')
|
|
assert asinh(x).rewrite(log) == log(x + sqrt(x**2 + 1))
|
|
assert asinh(x).rewrite(atanh) == atanh(x/sqrt(1 + x**2))
|
|
assert asinh(x).rewrite(asin) == asinh(x)
|
|
assert asinh(x*(1 + I)).rewrite(asin) == -I*asin(I*x*(1+I))
|
|
assert asinh(x).rewrite(acos) == I*(-I*asinh(x) + pi/2) - I*pi/2
|
|
|
|
|
|
def test_asinh_leading_term():
|
|
x = Symbol('x')
|
|
assert asinh(x).as_leading_term(x, cdir=1) == x
|
|
# Tests concerning branch points
|
|
assert asinh(x + I).as_leading_term(x, cdir=1) == I*pi/2
|
|
assert asinh(x - I).as_leading_term(x, cdir=1) == -I*pi/2
|
|
assert asinh(1/x).as_leading_term(x, cdir=1) == -log(x) + log(2)
|
|
assert asinh(1/x).as_leading_term(x, cdir=-1) == log(x) - log(2) - I*pi
|
|
# Tests concerning points lying on branch cuts
|
|
assert asinh(x + 2*I).as_leading_term(x, cdir=1) == I*asin(2)
|
|
assert asinh(x + 2*I).as_leading_term(x, cdir=-1) == -I*asin(2) + I*pi
|
|
assert asinh(x - 2*I).as_leading_term(x, cdir=1) == -I*pi + I*asin(2)
|
|
assert asinh(x - 2*I).as_leading_term(x, cdir=-1) == -I*asin(2)
|
|
# Tests concerning re(ndir) == 0
|
|
assert asinh(2*I + I*x - x**2).as_leading_term(x, cdir=1) == log(2 - sqrt(3)) + I*pi/2
|
|
assert asinh(2*I + I*x - x**2).as_leading_term(x, cdir=-1) == log(2 - sqrt(3)) + I*pi/2
|
|
|
|
|
|
def test_asinh_series():
|
|
x = Symbol('x')
|
|
assert asinh(x).series(x, 0, 8) == \
|
|
x - x**3/6 + 3*x**5/40 - 5*x**7/112 + O(x**8)
|
|
t5 = asinh(x).taylor_term(5, x)
|
|
assert t5 == 3*x**5/40
|
|
assert asinh(x).taylor_term(7, x, t5, 0) == -5*x**7/112
|
|
|
|
|
|
def test_asinh_nseries():
|
|
x = Symbol('x')
|
|
# Tests concerning branch points
|
|
assert asinh(x + I)._eval_nseries(x, 4, None) == I*pi/2 + \
|
|
sqrt(x)*(1 - I) + x**(S(3)/2)*(S(1)/12 + I/12) + x**(S(5)/2)*(-S(3)/160 + 3*I/160) + \
|
|
x**(S(7)/2)*(-S(5)/896 - 5*I/896) + O(x**4)
|
|
assert asinh(x - I)._eval_nseries(x, 4, None) == -I*pi/2 + \
|
|
sqrt(x)*(1 + I) + x**(S(3)/2)*(S(1)/12 - I/12) + x**(S(5)/2)*(-S(3)/160 - 3*I/160) + \
|
|
x**(S(7)/2)*(-S(5)/896 + 5*I/896) + O(x**4)
|
|
# Tests concerning points lying on branch cuts
|
|
assert asinh(x + 2*I)._eval_nseries(x, 4, None, cdir=1) == I*asin(2) - \
|
|
sqrt(3)*I*x/3 + sqrt(3)*x**2/9 + sqrt(3)*I*x**3/18 + O(x**4)
|
|
assert asinh(x + 2*I)._eval_nseries(x, 4, None, cdir=-1) == I*pi - I*asin(2) + \
|
|
sqrt(3)*I*x/3 - sqrt(3)*x**2/9 - sqrt(3)*I*x**3/18 + O(x**4)
|
|
assert asinh(x - 2*I)._eval_nseries(x, 4, None, cdir=1) == I*asin(2) - I*pi + \
|
|
sqrt(3)*I*x/3 + sqrt(3)*x**2/9 - sqrt(3)*I*x**3/18 + O(x**4)
|
|
assert asinh(x - 2*I)._eval_nseries(x, 4, None, cdir=-1) == -I*asin(2) - \
|
|
sqrt(3)*I*x/3 - sqrt(3)*x**2/9 + sqrt(3)*I*x**3/18 + O(x**4)
|
|
# Tests concerning re(ndir) == 0
|
|
assert asinh(2*I + I*x - x**2)._eval_nseries(x, 4, None) == I*pi/2 + log(2 - sqrt(3)) - \
|
|
sqrt(3)*x/3 + x**2*(sqrt(3)/9 - sqrt(3)*I/3) + x**3*(-sqrt(3)/18 + 2*sqrt(3)*I/9) + O(x**4)
|
|
|
|
|
|
def test_asinh_fdiff():
|
|
x = Symbol('x')
|
|
raises(ArgumentIndexError, lambda: asinh(x).fdiff(2))
|
|
|
|
|
|
def test_acosh():
|
|
x = Symbol('x')
|
|
|
|
assert unchanged(acosh, -x)
|
|
|
|
#at specific points
|
|
assert acosh(1) == 0
|
|
assert acosh(-1) == pi*I
|
|
assert acosh(0) == I*pi/2
|
|
assert acosh(S.Half) == I*pi/3
|
|
assert acosh(Rational(-1, 2)) == pi*I*Rational(2, 3)
|
|
assert acosh(nan) is nan
|
|
|
|
# at infinites
|
|
assert acosh(oo) is oo
|
|
assert acosh(-oo) is oo
|
|
|
|
assert acosh(I*oo) == oo + I*pi/2
|
|
assert acosh(-I*oo) == oo - I*pi/2
|
|
|
|
assert acosh(zoo) is zoo
|
|
|
|
assert acosh(I) == log(I*(1 + sqrt(2)))
|
|
assert acosh(-I) == log(-I*(1 + sqrt(2)))
|
|
assert acosh((sqrt(3) - 1)/(2*sqrt(2))) == pi*I*Rational(5, 12)
|
|
assert acosh(-(sqrt(3) - 1)/(2*sqrt(2))) == pi*I*Rational(7, 12)
|
|
assert acosh(sqrt(2)/2) == I*pi/4
|
|
assert acosh(-sqrt(2)/2) == I*pi*Rational(3, 4)
|
|
assert acosh(sqrt(3)/2) == I*pi/6
|
|
assert acosh(-sqrt(3)/2) == I*pi*Rational(5, 6)
|
|
assert acosh(sqrt(2 + sqrt(2))/2) == I*pi/8
|
|
assert acosh(-sqrt(2 + sqrt(2))/2) == I*pi*Rational(7, 8)
|
|
assert acosh(sqrt(2 - sqrt(2))/2) == I*pi*Rational(3, 8)
|
|
assert acosh(-sqrt(2 - sqrt(2))/2) == I*pi*Rational(5, 8)
|
|
assert acosh((1 + sqrt(3))/(2*sqrt(2))) == I*pi/12
|
|
assert acosh(-(1 + sqrt(3))/(2*sqrt(2))) == I*pi*Rational(11, 12)
|
|
assert acosh((sqrt(5) + 1)/4) == I*pi/5
|
|
assert acosh(-(sqrt(5) + 1)/4) == I*pi*Rational(4, 5)
|
|
|
|
assert str(acosh(5*I).n(6)) == '2.31244 + 1.5708*I'
|
|
assert str(acosh(-5*I).n(6)) == '2.31244 - 1.5708*I'
|
|
|
|
# inverse composition
|
|
assert unchanged(acosh, Symbol('v1'))
|
|
|
|
assert acosh(cosh(-3, evaluate=False)) == 3
|
|
assert acosh(cosh(3, evaluate=False)) == 3
|
|
assert acosh(cosh(0, evaluate=False)) == 0
|
|
assert acosh(cosh(I, evaluate=False)) == I
|
|
assert acosh(cosh(-I, evaluate=False)) == I
|
|
assert acosh(cosh(7*I, evaluate=False)) == -2*I*pi + 7*I
|
|
assert acosh(cosh(1 + I)) == 1 + I
|
|
assert acosh(cosh(3 - 3*I)) == 3 - 3*I
|
|
assert acosh(cosh(-3 + 2*I)) == 3 - 2*I
|
|
assert acosh(cosh(-5 - 17*I)) == 5 - 6*I*pi + 17*I
|
|
assert acosh(cosh(-21 + 11*I)) == 21 - 11*I + 4*I*pi
|
|
assert acosh(cosh(cosh(1) + I)) == cosh(1) + I
|
|
assert acosh(1, evaluate=False).is_zero is True
|
|
|
|
|
|
def test_acosh_rewrite():
|
|
x = Symbol('x')
|
|
assert acosh(x).rewrite(log) == log(x + sqrt(x - 1)*sqrt(x + 1))
|
|
assert acosh(x).rewrite(asin) == sqrt(x - 1)*(-asin(x) + pi/2)/sqrt(1 - x)
|
|
assert acosh(x).rewrite(asinh) == sqrt(x - 1)*(-asin(x) + pi/2)/sqrt(1 - x)
|
|
assert acosh(x).rewrite(atanh) == \
|
|
(sqrt(x - 1)*sqrt(x + 1)*atanh(sqrt(x**2 - 1)/x)/sqrt(x**2 - 1) +
|
|
pi*sqrt(x - 1)*(-x*sqrt(x**(-2)) + 1)/(2*sqrt(1 - x)))
|
|
x = Symbol('x', positive=True)
|
|
assert acosh(x).rewrite(atanh) == \
|
|
sqrt(x - 1)*sqrt(x + 1)*atanh(sqrt(x**2 - 1)/x)/sqrt(x**2 - 1)
|
|
|
|
|
|
def test_acosh_leading_term():
|
|
x = Symbol('x')
|
|
# Tests concerning branch points
|
|
assert acosh(x).as_leading_term(x) == I*pi/2
|
|
assert acosh(x + 1).as_leading_term(x) == sqrt(2)*sqrt(x)
|
|
assert acosh(x - 1).as_leading_term(x) == I*pi
|
|
assert acosh(1/x).as_leading_term(x, cdir=1) == -log(x) + log(2)
|
|
assert acosh(1/x).as_leading_term(x, cdir=-1) == -log(x) + log(2) + 2*I*pi
|
|
# Tests concerning points lying on branch cuts
|
|
assert acosh(I*x - 2).as_leading_term(x, cdir=1) == acosh(-2)
|
|
assert acosh(-I*x - 2).as_leading_term(x, cdir=1) == -2*I*pi + acosh(-2)
|
|
assert acosh(x**2 - I*x + S(1)/3).as_leading_term(x, cdir=1) == -acosh(S(1)/3)
|
|
assert acosh(x**2 - I*x + S(1)/3).as_leading_term(x, cdir=-1) == acosh(S(1)/3)
|
|
assert acosh(1/(I*x - 3)).as_leading_term(x, cdir=1) == -acosh(-S(1)/3)
|
|
assert acosh(1/(I*x - 3)).as_leading_term(x, cdir=-1) == acosh(-S(1)/3)
|
|
# Tests concerning im(ndir) == 0
|
|
assert acosh(-I*x**2 + x - 2).as_leading_term(x, cdir=1) == log(sqrt(3) + 2) - I*pi
|
|
assert acosh(-I*x**2 + x - 2).as_leading_term(x, cdir=-1) == log(sqrt(3) + 2) - I*pi
|
|
|
|
|
|
def test_acosh_series():
|
|
x = Symbol('x')
|
|
assert acosh(x).series(x, 0, 8) == \
|
|
-I*x + pi*I/2 - I*x**3/6 - 3*I*x**5/40 - 5*I*x**7/112 + O(x**8)
|
|
t5 = acosh(x).taylor_term(5, x)
|
|
assert t5 == - 3*I*x**5/40
|
|
assert acosh(x).taylor_term(7, x, t5, 0) == - 5*I*x**7/112
|
|
|
|
|
|
def test_acosh_nseries():
|
|
x = Symbol('x')
|
|
# Tests concerning branch points
|
|
assert acosh(x + 1)._eval_nseries(x, 4, None) == sqrt(2)*sqrt(x) - \
|
|
sqrt(2)*x**(S(3)/2)/12 + 3*sqrt(2)*x**(S(5)/2)/160 - 5*sqrt(2)*x**(S(7)/2)/896 + O(x**4)
|
|
# Tests concerning points lying on branch cuts
|
|
assert acosh(x - 1)._eval_nseries(x, 4, None) == I*pi - \
|
|
sqrt(2)*I*sqrt(x) - sqrt(2)*I*x**(S(3)/2)/12 - 3*sqrt(2)*I*x**(S(5)/2)/160 - \
|
|
5*sqrt(2)*I*x**(S(7)/2)/896 + O(x**4)
|
|
assert acosh(I*x - 2)._eval_nseries(x, 4, None, cdir=1) == acosh(-2) - \
|
|
sqrt(3)*I*x/3 + sqrt(3)*x**2/9 + sqrt(3)*I*x**3/18 + O(x**4)
|
|
assert acosh(-I*x - 2)._eval_nseries(x, 4, None, cdir=1) == acosh(-2) - \
|
|
2*I*pi + sqrt(3)*I*x/3 + sqrt(3)*x**2/9 - sqrt(3)*I*x**3/18 + O(x**4)
|
|
assert acosh(1/(I*x - 3))._eval_nseries(x, 4, None, cdir=1) == -acosh(-S(1)/3) + \
|
|
sqrt(2)*x/12 + 17*sqrt(2)*I*x**2/576 - 443*sqrt(2)*x**3/41472 + O(x**4)
|
|
assert acosh(1/(I*x - 3))._eval_nseries(x, 4, None, cdir=-1) == acosh(-S(1)/3) - \
|
|
sqrt(2)*x/12 - 17*sqrt(2)*I*x**2/576 + 443*sqrt(2)*x**3/41472 + O(x**4)
|
|
# Tests concerning im(ndir) == 0
|
|
assert acosh(-I*x**2 + x - 2)._eval_nseries(x, 4, None) == -I*pi + log(sqrt(3) + 2) - \
|
|
sqrt(3)*x/3 + x**2*(-sqrt(3)/9 + sqrt(3)*I/3) + x**3*(-sqrt(3)/18 + 2*sqrt(3)*I/9) + O(x**4)
|
|
|
|
|
|
def test_acosh_fdiff():
|
|
x = Symbol('x')
|
|
raises(ArgumentIndexError, lambda: acosh(x).fdiff(2))
|
|
|
|
|
|
def test_asech():
|
|
x = Symbol('x')
|
|
|
|
assert unchanged(asech, -x)
|
|
|
|
# values at fixed points
|
|
assert asech(1) == 0
|
|
assert asech(-1) == pi*I
|
|
assert asech(0) is oo
|
|
assert asech(2) == I*pi/3
|
|
assert asech(-2) == 2*I*pi / 3
|
|
assert asech(nan) is nan
|
|
|
|
# at infinites
|
|
assert asech(oo) == I*pi/2
|
|
assert asech(-oo) == I*pi/2
|
|
assert asech(zoo) == I*AccumBounds(-pi/2, pi/2)
|
|
|
|
assert asech(I) == log(1 + sqrt(2)) - I*pi/2
|
|
assert asech(-I) == log(1 + sqrt(2)) + I*pi/2
|
|
assert asech(sqrt(2) - sqrt(6)) == 11*I*pi / 12
|
|
assert asech(sqrt(2 - 2/sqrt(5))) == I*pi / 10
|
|
assert asech(-sqrt(2 - 2/sqrt(5))) == 9*I*pi / 10
|
|
assert asech(2 / sqrt(2 + sqrt(2))) == I*pi / 8
|
|
assert asech(-2 / sqrt(2 + sqrt(2))) == 7*I*pi / 8
|
|
assert asech(sqrt(5) - 1) == I*pi / 5
|
|
assert asech(1 - sqrt(5)) == 4*I*pi / 5
|
|
assert asech(-sqrt(2*(2 + sqrt(2)))) == 5*I*pi / 8
|
|
|
|
# properties
|
|
# asech(x) == acosh(1/x)
|
|
assert asech(sqrt(2)) == acosh(1/sqrt(2))
|
|
assert asech(2/sqrt(3)) == acosh(sqrt(3)/2)
|
|
assert asech(2/sqrt(2 + sqrt(2))) == acosh(sqrt(2 + sqrt(2))/2)
|
|
assert asech(2) == acosh(S.Half)
|
|
|
|
# asech(x) == I*acos(1/x)
|
|
# (Note: the exact formula is asech(x) == +/- I*acos(1/x))
|
|
assert asech(-sqrt(2)) == I*acos(-1/sqrt(2))
|
|
assert asech(-2/sqrt(3)) == I*acos(-sqrt(3)/2)
|
|
assert asech(-S(2)) == I*acos(Rational(-1, 2))
|
|
assert asech(-2/sqrt(2)) == I*acos(-sqrt(2)/2)
|
|
|
|
# sech(asech(x)) / x == 1
|
|
assert expand_mul(sech(asech(sqrt(6) - sqrt(2))) / (sqrt(6) - sqrt(2))) == 1
|
|
assert expand_mul(sech(asech(sqrt(6) + sqrt(2))) / (sqrt(6) + sqrt(2))) == 1
|
|
assert (sech(asech(sqrt(2 + 2/sqrt(5)))) / (sqrt(2 + 2/sqrt(5)))).simplify() == 1
|
|
assert (sech(asech(-sqrt(2 + 2/sqrt(5)))) / (-sqrt(2 + 2/sqrt(5)))).simplify() == 1
|
|
assert (sech(asech(sqrt(2*(2 + sqrt(2))))) / (sqrt(2*(2 + sqrt(2))))).simplify() == 1
|
|
assert expand_mul(sech(asech(1 + sqrt(5))) / (1 + sqrt(5))) == 1
|
|
assert expand_mul(sech(asech(-1 - sqrt(5))) / (-1 - sqrt(5))) == 1
|
|
assert expand_mul(sech(asech(-sqrt(6) - sqrt(2))) / (-sqrt(6) - sqrt(2))) == 1
|
|
|
|
# numerical evaluation
|
|
assert str(asech(5*I).n(6)) == '0.19869 - 1.5708*I'
|
|
assert str(asech(-5*I).n(6)) == '0.19869 + 1.5708*I'
|
|
|
|
|
|
def test_asech_leading_term():
|
|
x = Symbol('x')
|
|
# Tests concerning branch points
|
|
assert asech(x).as_leading_term(x, cdir=1) == -log(x) + log(2)
|
|
assert asech(x).as_leading_term(x, cdir=-1) == -log(x) + log(2) + 2*I*pi
|
|
assert asech(x + 1).as_leading_term(x, cdir=1) == sqrt(2)*I*sqrt(x)
|
|
assert asech(1/x).as_leading_term(x, cdir=1) == I*pi/2
|
|
# Tests concerning points lying on branch cuts
|
|
assert asech(x - 1).as_leading_term(x, cdir=1) == I*pi
|
|
assert asech(I*x + 3).as_leading_term(x, cdir=1) == -asech(3)
|
|
assert asech(-I*x + 3).as_leading_term(x, cdir=1) == asech(3)
|
|
assert asech(I*x - 3).as_leading_term(x, cdir=1) == -asech(-3)
|
|
assert asech(-I*x - 3).as_leading_term(x, cdir=1) == asech(-3)
|
|
assert asech(I*x - S(1)/3).as_leading_term(x, cdir=1) == -2*I*pi + asech(-S(1)/3)
|
|
assert asech(I*x - S(1)/3).as_leading_term(x, cdir=-1) == asech(-S(1)/3)
|
|
# Tests concerning im(ndir) == 0
|
|
assert asech(-I*x**2 + x - 3).as_leading_term(x, cdir=1) == log(-S(1)/3 + 2*sqrt(2)*I/3)
|
|
assert asech(-I*x**2 + x - 3).as_leading_term(x, cdir=-1) == log(-S(1)/3 + 2*sqrt(2)*I/3)
|
|
|
|
|
|
def test_asech_series():
|
|
x = Symbol('x')
|
|
assert asech(x).series(x, 0, 9, cdir=1) == log(2) - log(x) - x**2/4 - 3*x**4/32 \
|
|
- 5*x**6/96 - 35*x**8/1024 + O(x**9)
|
|
assert asech(x).series(x, 0, 9, cdir=-1) == I*pi + log(2) - log(-x) - x**2/4 - \
|
|
3*x**4/32 - 5*x**6/96 - 35*x**8/1024 + O(x**9)
|
|
t6 = asech(x).taylor_term(6, x)
|
|
assert t6 == -5*x**6/96
|
|
assert asech(x).taylor_term(8, x, t6, 0) == -35*x**8/1024
|
|
|
|
|
|
def test_asech_nseries():
|
|
x = Symbol('x')
|
|
# Tests concerning branch points
|
|
assert asech(x + 1)._eval_nseries(x, 4, None) == sqrt(2)*sqrt(-x) + 5*sqrt(2)*(-x)**(S(3)/2)/12 + \
|
|
43*sqrt(2)*(-x)**(S(5)/2)/160 + 177*sqrt(2)*(-x)**(S(7)/2)/896 + O(x**4)
|
|
# Tests concerning points lying on branch cuts
|
|
assert asech(x - 1)._eval_nseries(x, 4, None) == I*pi + sqrt(2)*sqrt(x) + \
|
|
5*sqrt(2)*x**(S(3)/2)/12 + 43*sqrt(2)*x**(S(5)/2)/160 + 177*sqrt(2)*x**(S(7)/2)/896 + O(x**4)
|
|
assert asech(I*x + 3)._eval_nseries(x, 4, None) == -asech(3) + sqrt(2)*x/12 - \
|
|
17*sqrt(2)*I*x**2/576 - 443*sqrt(2)*x**3/41472 + O(x**4)
|
|
assert asech(-I*x + 3)._eval_nseries(x, 4, None) == asech(3) + sqrt(2)*x/12 + \
|
|
17*sqrt(2)*I*x**2/576 - 443*sqrt(2)*x**3/41472 + O(x**4)
|
|
assert asech(I*x - 3)._eval_nseries(x, 4, None) == -asech(-3) - sqrt(2)*x/12 - \
|
|
17*sqrt(2)*I*x**2/576 + 443*sqrt(2)*x**3/41472 + O(x**4)
|
|
assert asech(-I*x - 3)._eval_nseries(x, 4, None) == asech(-3) - sqrt(2)*x/12 + \
|
|
17*sqrt(2)*I*x**2/576 + 443*sqrt(2)*x**3/41472 + O(x**4)
|
|
# Tests concerning im(ndir) == 0
|
|
assert asech(-I*x**2 + x - 2)._eval_nseries(x, 3, None) == 2*I*pi/3 + sqrt(3)*I*x/6 + \
|
|
x**2*(sqrt(3)/6 + 7*sqrt(3)*I/72) + O(x**3)
|
|
|
|
|
|
def test_asech_rewrite():
|
|
x = Symbol('x')
|
|
assert asech(x).rewrite(log) == log(1/x + sqrt(1/x - 1) * sqrt(1/x + 1))
|
|
assert asech(x).rewrite(acosh) == acosh(1/x)
|
|
assert asech(x).rewrite(asinh) == sqrt(-1 + 1/x)*(-asin(1/x) + pi/2)/sqrt(1 - 1/x)
|
|
assert asech(x).rewrite(atanh) == \
|
|
sqrt(x + 1)*sqrt(1/(x + 1))*atanh(sqrt(1 - x**2)) + I*pi*(-sqrt(x)*sqrt(1/x) + 1 - I*sqrt(x**2)/(2*sqrt(-x**2)) - I*sqrt(-x)/(2*sqrt(x)))
|
|
|
|
|
|
def test_asech_fdiff():
|
|
x = Symbol('x')
|
|
raises(ArgumentIndexError, lambda: asech(x).fdiff(2))
|
|
|
|
|
|
def test_acsch():
|
|
x = Symbol('x')
|
|
|
|
assert unchanged(acsch, x)
|
|
assert acsch(-x) == -acsch(x)
|
|
|
|
# values at fixed points
|
|
assert acsch(1) == log(1 + sqrt(2))
|
|
assert acsch(-1) == - log(1 + sqrt(2))
|
|
assert acsch(0) is zoo
|
|
assert acsch(2) == log((1+sqrt(5))/2)
|
|
assert acsch(-2) == - log((1+sqrt(5))/2)
|
|
|
|
assert acsch(I) == - I*pi/2
|
|
assert acsch(-I) == I*pi/2
|
|
assert acsch(-I*(sqrt(6) + sqrt(2))) == I*pi / 12
|
|
assert acsch(I*(sqrt(2) + sqrt(6))) == -I*pi / 12
|
|
assert acsch(-I*(1 + sqrt(5))) == I*pi / 10
|
|
assert acsch(I*(1 + sqrt(5))) == -I*pi / 10
|
|
assert acsch(-I*2 / sqrt(2 - sqrt(2))) == I*pi / 8
|
|
assert acsch(I*2 / sqrt(2 - sqrt(2))) == -I*pi / 8
|
|
assert acsch(-I*2) == I*pi / 6
|
|
assert acsch(I*2) == -I*pi / 6
|
|
assert acsch(-I*sqrt(2 + 2/sqrt(5))) == I*pi / 5
|
|
assert acsch(I*sqrt(2 + 2/sqrt(5))) == -I*pi / 5
|
|
assert acsch(-I*sqrt(2)) == I*pi / 4
|
|
assert acsch(I*sqrt(2)) == -I*pi / 4
|
|
assert acsch(-I*(sqrt(5)-1)) == 3*I*pi / 10
|
|
assert acsch(I*(sqrt(5)-1)) == -3*I*pi / 10
|
|
assert acsch(-I*2 / sqrt(3)) == I*pi / 3
|
|
assert acsch(I*2 / sqrt(3)) == -I*pi / 3
|
|
assert acsch(-I*2 / sqrt(2 + sqrt(2))) == 3*I*pi / 8
|
|
assert acsch(I*2 / sqrt(2 + sqrt(2))) == -3*I*pi / 8
|
|
assert acsch(-I*sqrt(2 - 2/sqrt(5))) == 2*I*pi / 5
|
|
assert acsch(I*sqrt(2 - 2/sqrt(5))) == -2*I*pi / 5
|
|
assert acsch(-I*(sqrt(6) - sqrt(2))) == 5*I*pi / 12
|
|
assert acsch(I*(sqrt(6) - sqrt(2))) == -5*I*pi / 12
|
|
assert acsch(nan) is nan
|
|
|
|
# properties
|
|
# acsch(x) == asinh(1/x)
|
|
assert acsch(-I*sqrt(2)) == asinh(I/sqrt(2))
|
|
assert acsch(-I*2 / sqrt(3)) == asinh(I*sqrt(3) / 2)
|
|
|
|
# acsch(x) == -I*asin(I/x)
|
|
assert acsch(-I*sqrt(2)) == -I*asin(-1/sqrt(2))
|
|
assert acsch(-I*2 / sqrt(3)) == -I*asin(-sqrt(3)/2)
|
|
|
|
# csch(acsch(x)) / x == 1
|
|
assert expand_mul(csch(acsch(-I*(sqrt(6) + sqrt(2)))) / (-I*(sqrt(6) + sqrt(2)))) == 1
|
|
assert expand_mul(csch(acsch(I*(1 + sqrt(5)))) / (I*(1 + sqrt(5)))) == 1
|
|
assert (csch(acsch(I*sqrt(2 - 2/sqrt(5)))) / (I*sqrt(2 - 2/sqrt(5)))).simplify() == 1
|
|
assert (csch(acsch(-I*sqrt(2 - 2/sqrt(5)))) / (-I*sqrt(2 - 2/sqrt(5)))).simplify() == 1
|
|
|
|
# numerical evaluation
|
|
assert str(acsch(5*I+1).n(6)) == '0.0391819 - 0.193363*I'
|
|
assert str(acsch(-5*I+1).n(6)) == '0.0391819 + 0.193363*I'
|
|
|
|
|
|
def test_acsch_infinities():
|
|
assert acsch(oo) == 0
|
|
assert acsch(-oo) == 0
|
|
assert acsch(zoo) == 0
|
|
|
|
|
|
def test_acsch_leading_term():
|
|
x = Symbol('x')
|
|
assert acsch(1/x).as_leading_term(x) == x
|
|
# Tests concerning branch points
|
|
assert acsch(x + I).as_leading_term(x) == -I*pi/2
|
|
assert acsch(x - I).as_leading_term(x) == I*pi/2
|
|
# Tests concerning points lying on branch cuts
|
|
assert acsch(x).as_leading_term(x, cdir=1) == -log(x) + log(2)
|
|
assert acsch(x).as_leading_term(x, cdir=-1) == log(x) - log(2) - I*pi
|
|
assert acsch(x + I/2).as_leading_term(x, cdir=1) == -I*pi - acsch(I/2)
|
|
assert acsch(x + I/2).as_leading_term(x, cdir=-1) == acsch(I/2)
|
|
assert acsch(x - I/2).as_leading_term(x, cdir=1) == -acsch(I/2)
|
|
assert acsch(x - I/2).as_leading_term(x, cdir=-1) == acsch(I/2) + I*pi
|
|
# Tests concerning re(ndir) == 0
|
|
assert acsch(I/2 + I*x - x**2).as_leading_term(x, cdir=1) == log(2 - sqrt(3)) - I*pi/2
|
|
assert acsch(I/2 + I*x - x**2).as_leading_term(x, cdir=-1) == log(2 - sqrt(3)) - I*pi/2
|
|
|
|
|
|
def test_acsch_series():
|
|
x = Symbol('x')
|
|
assert acsch(x).series(x, 0, 9) == log(2) - log(x) + x**2/4 - 3*x**4/32 \
|
|
+ 5*x**6/96 - 35*x**8/1024 + O(x**9)
|
|
t4 = acsch(x).taylor_term(4, x)
|
|
assert t4 == -3*x**4/32
|
|
assert acsch(x).taylor_term(6, x, t4, 0) == 5*x**6/96
|
|
|
|
|
|
def test_acsch_nseries():
|
|
x = Symbol('x')
|
|
# Tests concerning branch points
|
|
assert acsch(x + I)._eval_nseries(x, 4, None) == -I*pi/2 + I*sqrt(x) + \
|
|
sqrt(x) + 5*I*x**(S(3)/2)/12 - 5*x**(S(3)/2)/12 - 43*I*x**(S(5)/2)/160 - \
|
|
43*x**(S(5)/2)/160 - 177*I*x**(S(7)/2)/896 + 177*x**(S(7)/2)/896 + O(x**4)
|
|
assert acsch(x - I)._eval_nseries(x, 4, None) == I*pi/2 - I*sqrt(x) + \
|
|
sqrt(x) - 5*I*x**(S(3)/2)/12 - 5*x**(S(3)/2)/12 + 43*I*x**(S(5)/2)/160 - \
|
|
43*x**(S(5)/2)/160 + 177*I*x**(S(7)/2)/896 + 177*x**(S(7)/2)/896 + O(x**4)
|
|
# Tests concerning points lying on branch cuts
|
|
assert acsch(x + I/2)._eval_nseries(x, 4, None, cdir=1) == -acsch(I/2) - \
|
|
I*pi + 4*sqrt(3)*I*x/3 - 8*sqrt(3)*x**2/9 - 16*sqrt(3)*I*x**3/9 + O(x**4)
|
|
assert acsch(x + I/2)._eval_nseries(x, 4, None, cdir=-1) == acsch(I/2) - \
|
|
4*sqrt(3)*I*x/3 + 8*sqrt(3)*x**2/9 + 16*sqrt(3)*I*x**3/9 + O(x**4)
|
|
assert acsch(x - I/2)._eval_nseries(x, 4, None, cdir=1) == -acsch(I/2) - \
|
|
4*sqrt(3)*I*x/3 - 8*sqrt(3)*x**2/9 + 16*sqrt(3)*I*x**3/9 + O(x**4)
|
|
assert acsch(x - I/2)._eval_nseries(x, 4, None, cdir=-1) == I*pi + \
|
|
acsch(I/2) + 4*sqrt(3)*I*x/3 + 8*sqrt(3)*x**2/9 - 16*sqrt(3)*I*x**3/9 + O(x**4)
|
|
# TODO: Tests concerning re(ndir) == 0
|
|
assert acsch(I/2 + I*x - x**2)._eval_nseries(x, 4, None) == -I*pi/2 + \
|
|
log(2 - sqrt(3)) + 4*sqrt(3)*x/3 + x**2*(-8*sqrt(3)/9 + 4*sqrt(3)*I/3) + \
|
|
x**3*(16*sqrt(3)/9 - 16*sqrt(3)*I/9) + O(x**4)
|
|
|
|
|
|
def test_acsch_rewrite():
|
|
x = Symbol('x')
|
|
assert acsch(x).rewrite(log) == log(1/x + sqrt(1/x**2 + 1))
|
|
assert acsch(x).rewrite(asinh) == asinh(1/x)
|
|
assert acsch(x).rewrite(atanh) == (sqrt(-x**2)*(-sqrt(-(x**2 + 1)**2)
|
|
*atanh(sqrt(x**2 + 1))/(x**2 + 1)
|
|
+ pi/2)/x)
|
|
|
|
|
|
def test_acsch_fdiff():
|
|
x = Symbol('x')
|
|
raises(ArgumentIndexError, lambda: acsch(x).fdiff(2))
|
|
|
|
|
|
def test_atanh():
|
|
x = Symbol('x')
|
|
|
|
#at specific points
|
|
assert atanh(0) == 0
|
|
assert atanh(I) == I*pi/4
|
|
assert atanh(-I) == -I*pi/4
|
|
assert atanh(1) is oo
|
|
assert atanh(-1) is -oo
|
|
assert atanh(nan) is nan
|
|
|
|
# at infinites
|
|
assert atanh(oo) == -I*pi/2
|
|
assert atanh(-oo) == I*pi/2
|
|
|
|
assert atanh(I*oo) == I*pi/2
|
|
assert atanh(-I*oo) == -I*pi/2
|
|
|
|
assert atanh(zoo) == I*AccumBounds(-pi/2, pi/2)
|
|
|
|
#properties
|
|
assert atanh(-x) == -atanh(x)
|
|
|
|
assert atanh(I/sqrt(3)) == I*pi/6
|
|
assert atanh(-I/sqrt(3)) == -I*pi/6
|
|
assert atanh(I*sqrt(3)) == I*pi/3
|
|
assert atanh(-I*sqrt(3)) == -I*pi/3
|
|
assert atanh(I*(1 + sqrt(2))) == pi*I*Rational(3, 8)
|
|
assert atanh(I*(sqrt(2) - 1)) == pi*I/8
|
|
assert atanh(I*(1 - sqrt(2))) == -pi*I/8
|
|
assert atanh(-I*(1 + sqrt(2))) == pi*I*Rational(-3, 8)
|
|
assert atanh(I*sqrt(5 + 2*sqrt(5))) == I*pi*Rational(2, 5)
|
|
assert atanh(-I*sqrt(5 + 2*sqrt(5))) == I*pi*Rational(-2, 5)
|
|
assert atanh(I*(2 - sqrt(3))) == pi*I/12
|
|
assert atanh(I*(sqrt(3) - 2)) == -pi*I/12
|
|
assert atanh(oo) == -I*pi/2
|
|
|
|
# Symmetry
|
|
assert atanh(Rational(-1, 2)) == -atanh(S.Half)
|
|
|
|
# inverse composition
|
|
assert unchanged(atanh, tanh(Symbol('v1')))
|
|
|
|
assert atanh(tanh(-5, evaluate=False)) == -5
|
|
assert atanh(tanh(0, evaluate=False)) == 0
|
|
assert atanh(tanh(7, evaluate=False)) == 7
|
|
assert atanh(tanh(I, evaluate=False)) == I
|
|
assert atanh(tanh(-I, evaluate=False)) == -I
|
|
assert atanh(tanh(-11*I, evaluate=False)) == -11*I + 4*I*pi
|
|
assert atanh(tanh(3 + I)) == 3 + I
|
|
assert atanh(tanh(4 + 5*I)) == 4 - 2*I*pi + 5*I
|
|
assert atanh(tanh(pi/2)) == pi/2
|
|
assert atanh(tanh(pi)) == pi
|
|
assert atanh(tanh(-3 + 7*I)) == -3 - 2*I*pi + 7*I
|
|
assert atanh(tanh(9 - I*2/3)) == 9 - I*2/3
|
|
assert atanh(tanh(-32 - 123*I)) == -32 - 123*I + 39*I*pi
|
|
|
|
|
|
def test_atanh_rewrite():
|
|
x = Symbol('x')
|
|
assert atanh(x).rewrite(log) == (log(1 + x) - log(1 - x)) / 2
|
|
assert atanh(x).rewrite(asinh) == \
|
|
pi*x/(2*sqrt(-x**2)) - sqrt(-x)*sqrt(1 - x**2)*sqrt(1/(x**2 - 1))*asinh(sqrt(1/(x**2 - 1)))/sqrt(x)
|
|
|
|
|
|
def test_atanh_leading_term():
|
|
x = Symbol('x')
|
|
assert atanh(x).as_leading_term(x) == x
|
|
# Tests concerning branch points
|
|
assert atanh(x + 1).as_leading_term(x, cdir=1) == -log(x)/2 + log(2)/2 - I*pi/2
|
|
assert atanh(x + 1).as_leading_term(x, cdir=-1) == -log(x)/2 + log(2)/2 + I*pi/2
|
|
assert atanh(x - 1).as_leading_term(x, cdir=1) == log(x)/2 - log(2)/2
|
|
assert atanh(x - 1).as_leading_term(x, cdir=-1) == log(x)/2 - log(2)/2
|
|
assert atanh(1/x).as_leading_term(x, cdir=1) == -I*pi/2
|
|
assert atanh(1/x).as_leading_term(x, cdir=-1) == I*pi/2
|
|
# Tests concerning points lying on branch cuts
|
|
assert atanh(I*x + 2).as_leading_term(x, cdir=1) == atanh(2) + I*pi
|
|
assert atanh(-I*x + 2).as_leading_term(x, cdir=1) == atanh(2)
|
|
assert atanh(I*x - 2).as_leading_term(x, cdir=1) == -atanh(2)
|
|
assert atanh(-I*x - 2).as_leading_term(x, cdir=1) == -I*pi - atanh(2)
|
|
# Tests concerning im(ndir) == 0
|
|
assert atanh(-I*x**2 + x - 2).as_leading_term(x, cdir=1) == -log(3)/2 - I*pi/2
|
|
assert atanh(-I*x**2 + x - 2).as_leading_term(x, cdir=-1) == -log(3)/2 - I*pi/2
|
|
|
|
|
|
def test_atanh_series():
|
|
x = Symbol('x')
|
|
assert atanh(x).series(x, 0, 10) == \
|
|
x + x**3/3 + x**5/5 + x**7/7 + x**9/9 + O(x**10)
|
|
|
|
|
|
def test_atanh_nseries():
|
|
x = Symbol('x')
|
|
# Tests concerning branch points
|
|
assert atanh(x + 1)._eval_nseries(x, 4, None, cdir=1) == -I*pi/2 + log(2)/2 - \
|
|
log(x)/2 + x/4 - x**2/16 + x**3/48 + O(x**4)
|
|
assert atanh(x + 1)._eval_nseries(x, 4, None, cdir=-1) == I*pi/2 + log(2)/2 - \
|
|
log(x)/2 + x/4 - x**2/16 + x**3/48 + O(x**4)
|
|
assert atanh(x - 1)._eval_nseries(x, 4, None, cdir=1) == -log(2)/2 + log(x)/2 + \
|
|
x/4 + x**2/16 + x**3/48 + O(x**4)
|
|
assert atanh(x - 1)._eval_nseries(x, 4, None, cdir=-1) == -log(2)/2 + log(x)/2 + \
|
|
x/4 + x**2/16 + x**3/48 + O(x**4)
|
|
# Tests concerning points lying on branch cuts
|
|
assert atanh(I*x + 2)._eval_nseries(x, 4, None, cdir=1) == I*pi + atanh(2) - \
|
|
I*x/3 - 2*x**2/9 + 13*I*x**3/81 + O(x**4)
|
|
assert atanh(I*x + 2)._eval_nseries(x, 4, None, cdir=-1) == atanh(2) - I*x/3 - \
|
|
2*x**2/9 + 13*I*x**3/81 + O(x**4)
|
|
assert atanh(I*x - 2)._eval_nseries(x, 4, None, cdir=1) == -atanh(2) - I*x/3 + \
|
|
2*x**2/9 + 13*I*x**3/81 + O(x**4)
|
|
assert atanh(I*x - 2)._eval_nseries(x, 4, None, cdir=-1) == -atanh(2) - I*pi - \
|
|
I*x/3 + 2*x**2/9 + 13*I*x**3/81 + O(x**4)
|
|
# Tests concerning im(ndir) == 0
|
|
assert atanh(-I*x**2 + x - 2)._eval_nseries(x, 4, None) == -I*pi/2 - log(3)/2 - x/3 + \
|
|
x**2*(-S(1)/4 + I/2) + x**2*(S(1)/36 - I/6) + x**3*(-S(1)/6 + I/2) + x**3*(S(1)/162 - I/18) + O(x**4)
|
|
|
|
|
|
def test_atanh_fdiff():
|
|
x = Symbol('x')
|
|
raises(ArgumentIndexError, lambda: atanh(x).fdiff(2))
|
|
|
|
|
|
def test_acoth():
|
|
x = Symbol('x')
|
|
|
|
#at specific points
|
|
assert acoth(0) == I*pi/2
|
|
assert acoth(I) == -I*pi/4
|
|
assert acoth(-I) == I*pi/4
|
|
assert acoth(1) is oo
|
|
assert acoth(-1) is -oo
|
|
assert acoth(nan) is nan
|
|
|
|
# at infinites
|
|
assert acoth(oo) == 0
|
|
assert acoth(-oo) == 0
|
|
assert acoth(I*oo) == 0
|
|
assert acoth(-I*oo) == 0
|
|
assert acoth(zoo) == 0
|
|
|
|
#properties
|
|
assert acoth(-x) == -acoth(x)
|
|
|
|
assert acoth(I/sqrt(3)) == -I*pi/3
|
|
assert acoth(-I/sqrt(3)) == I*pi/3
|
|
assert acoth(I*sqrt(3)) == -I*pi/6
|
|
assert acoth(-I*sqrt(3)) == I*pi/6
|
|
assert acoth(I*(1 + sqrt(2))) == -pi*I/8
|
|
assert acoth(-I*(sqrt(2) + 1)) == pi*I/8
|
|
assert acoth(I*(1 - sqrt(2))) == pi*I*Rational(3, 8)
|
|
assert acoth(I*(sqrt(2) - 1)) == pi*I*Rational(-3, 8)
|
|
assert acoth(I*sqrt(5 + 2*sqrt(5))) == -I*pi/10
|
|
assert acoth(-I*sqrt(5 + 2*sqrt(5))) == I*pi/10
|
|
assert acoth(I*(2 + sqrt(3))) == -pi*I/12
|
|
assert acoth(-I*(2 + sqrt(3))) == pi*I/12
|
|
assert acoth(I*(2 - sqrt(3))) == pi*I*Rational(-5, 12)
|
|
assert acoth(I*(sqrt(3) - 2)) == pi*I*Rational(5, 12)
|
|
|
|
# Symmetry
|
|
assert acoth(Rational(-1, 2)) == -acoth(S.Half)
|
|
|
|
|
|
def test_acoth_rewrite():
|
|
x = Symbol('x')
|
|
assert acoth(x).rewrite(log) == (log(1 + 1/x) - log(1 - 1/x)) / 2
|
|
assert acoth(x).rewrite(atanh) == atanh(1/x)
|
|
assert acoth(x).rewrite(asinh) == \
|
|
x*sqrt(x**(-2))*asinh(sqrt(1/(x**2 - 1))) + I*pi*(sqrt((x - 1)/x)*sqrt(x/(x - 1)) - sqrt(x/(x + 1))*sqrt(1 + 1/x))/2
|
|
|
|
|
|
def test_acoth_leading_term():
|
|
x = Symbol('x')
|
|
# Tests concerning branch points
|
|
assert acoth(x + 1).as_leading_term(x, cdir=1) == -log(x)/2 + log(2)/2
|
|
assert acoth(x + 1).as_leading_term(x, cdir=-1) == -log(x)/2 + log(2)/2
|
|
assert acoth(x - 1).as_leading_term(x, cdir=1) == log(x)/2 - log(2)/2 + I*pi/2
|
|
assert acoth(x - 1).as_leading_term(x, cdir=-1) == log(x)/2 - log(2)/2 - I*pi/2
|
|
# Tests concerning points lying on branch cuts
|
|
assert acoth(x).as_leading_term(x, cdir=-1) == I*pi/2
|
|
assert acoth(x).as_leading_term(x, cdir=1) == -I*pi/2
|
|
assert acoth(I*x + 1/2).as_leading_term(x, cdir=1) == acoth(1/2)
|
|
assert acoth(-I*x + 1/2).as_leading_term(x, cdir=1) == acoth(1/2) + I*pi
|
|
assert acoth(I*x - 1/2).as_leading_term(x, cdir=1) == -I*pi - acoth(1/2)
|
|
assert acoth(-I*x - 1/2).as_leading_term(x, cdir=1) == -acoth(1/2)
|
|
# Tests concerning im(ndir) == 0
|
|
assert acoth(-I*x**2 - x - S(1)/2).as_leading_term(x, cdir=1) == -log(3)/2 + I*pi/2
|
|
assert acoth(-I*x**2 - x - S(1)/2).as_leading_term(x, cdir=-1) == -log(3)/2 + I*pi/2
|
|
|
|
|
|
def test_acoth_series():
|
|
x = Symbol('x')
|
|
assert acoth(x).series(x, 0, 10) == \
|
|
-I*pi/2 + x + x**3/3 + x**5/5 + x**7/7 + x**9/9 + O(x**10)
|
|
|
|
|
|
def test_acoth_nseries():
|
|
x = Symbol('x')
|
|
# Tests concerning branch points
|
|
assert acoth(x + 1)._eval_nseries(x, 4, None) == log(2)/2 - log(x)/2 + x/4 - \
|
|
x**2/16 + x**3/48 + O(x**4)
|
|
assert acoth(x - 1)._eval_nseries(x, 4, None, cdir=1) == I*pi/2 - log(2)/2 + \
|
|
log(x)/2 + x/4 + x**2/16 + x**3/48 + O(x**4)
|
|
assert acoth(x - 1)._eval_nseries(x, 4, None, cdir=-1) == -I*pi/2 - log(2)/2 + \
|
|
log(x)/2 + x/4 + x**2/16 + x**3/48 + O(x**4)
|
|
# Tests concerning points lying on branch cuts
|
|
assert acoth(I*x + S(1)/2)._eval_nseries(x, 4, None, cdir=1) == acoth(S(1)/2) + \
|
|
4*I*x/3 - 8*x**2/9 - 112*I*x**3/81 + O(x**4)
|
|
assert acoth(I*x + S(1)/2)._eval_nseries(x, 4, None, cdir=-1) == I*pi + \
|
|
acoth(S(1)/2) + 4*I*x/3 - 8*x**2/9 - 112*I*x**3/81 + O(x**4)
|
|
assert acoth(I*x - S(1)/2)._eval_nseries(x, 4, None, cdir=1) == -acoth(S(1)/2) - \
|
|
I*pi + 4*I*x/3 + 8*x**2/9 - 112*I*x**3/81 + O(x**4)
|
|
assert acoth(I*x - S(1)/2)._eval_nseries(x, 4, None, cdir=-1) == -acoth(S(1)/2) + \
|
|
4*I*x/3 + 8*x**2/9 - 112*I*x**3/81 + O(x**4)
|
|
# Tests concerning im(ndir) == 0
|
|
assert acoth(-I*x**2 - x - S(1)/2)._eval_nseries(x, 4, None) == I*pi/2 - log(3)/2 - \
|
|
4*x/3 + x**2*(-S(8)/9 + 2*I/3) - 2*I*x**2 + x**3*(S(104)/81 - 16*I/9) - 8*x**3/3 + O(x**4)
|
|
|
|
|
|
def test_acoth_fdiff():
|
|
x = Symbol('x')
|
|
raises(ArgumentIndexError, lambda: acoth(x).fdiff(2))
|
|
|
|
|
|
def test_inverses():
|
|
x = Symbol('x')
|
|
assert sinh(x).inverse() == asinh
|
|
raises(AttributeError, lambda: cosh(x).inverse())
|
|
assert tanh(x).inverse() == atanh
|
|
assert coth(x).inverse() == acoth
|
|
assert asinh(x).inverse() == sinh
|
|
assert acosh(x).inverse() == cosh
|
|
assert atanh(x).inverse() == tanh
|
|
assert acoth(x).inverse() == coth
|
|
assert asech(x).inverse() == sech
|
|
assert acsch(x).inverse() == csch
|
|
|
|
|
|
def test_leading_term():
|
|
x = Symbol('x')
|
|
assert cosh(x).as_leading_term(x) == 1
|
|
assert coth(x).as_leading_term(x) == 1/x
|
|
for func in [sinh, tanh]:
|
|
assert func(x).as_leading_term(x) == x
|
|
for func in [sinh, cosh, tanh, coth]:
|
|
for ar in (1/x, S.Half):
|
|
eq = func(ar)
|
|
assert eq.as_leading_term(x) == eq
|
|
for func in [csch, sech]:
|
|
eq = func(S.Half)
|
|
assert eq.as_leading_term(x) == eq
|
|
|
|
|
|
def test_complex():
|
|
a, b = symbols('a,b', real=True)
|
|
z = a + b*I
|
|
for func in [sinh, cosh, tanh, coth, sech, csch]:
|
|
assert func(z).conjugate() == func(a - b*I)
|
|
for deep in [True, False]:
|
|
assert sinh(z).expand(
|
|
complex=True, deep=deep) == sinh(a)*cos(b) + I*cosh(a)*sin(b)
|
|
assert cosh(z).expand(
|
|
complex=True, deep=deep) == cosh(a)*cos(b) + I*sinh(a)*sin(b)
|
|
assert tanh(z).expand(complex=True, deep=deep) == sinh(a)*cosh(
|
|
a)/(cos(b)**2 + sinh(a)**2) + I*sin(b)*cos(b)/(cos(b)**2 + sinh(a)**2)
|
|
assert coth(z).expand(complex=True, deep=deep) == sinh(a)*cosh(
|
|
a)/(sin(b)**2 + sinh(a)**2) - I*sin(b)*cos(b)/(sin(b)**2 + sinh(a)**2)
|
|
assert csch(z).expand(complex=True, deep=deep) == cos(b) * sinh(a) / (sin(b)**2\
|
|
*cosh(a)**2 + cos(b)**2 * sinh(a)**2) - I*sin(b) * cosh(a) / (sin(b)**2\
|
|
*cosh(a)**2 + cos(b)**2 * sinh(a)**2)
|
|
assert sech(z).expand(complex=True, deep=deep) == cos(b) * cosh(a) / (sin(b)**2\
|
|
*sinh(a)**2 + cos(b)**2 * cosh(a)**2) - I*sin(b) * sinh(a) / (sin(b)**2\
|
|
*sinh(a)**2 + cos(b)**2 * cosh(a)**2)
|
|
|
|
|
|
def test_complex_2899():
|
|
a, b = symbols('a,b', real=True)
|
|
for deep in [True, False]:
|
|
for func in [sinh, cosh, tanh, coth]:
|
|
assert func(a).expand(complex=True, deep=deep) == func(a)
|
|
|
|
|
|
def test_simplifications():
|
|
x = Symbol('x')
|
|
assert sinh(asinh(x)) == x
|
|
assert sinh(acosh(x)) == sqrt(x - 1) * sqrt(x + 1)
|
|
assert sinh(atanh(x)) == x/sqrt(1 - x**2)
|
|
assert sinh(acoth(x)) == 1/(sqrt(x - 1) * sqrt(x + 1))
|
|
|
|
assert cosh(asinh(x)) == sqrt(1 + x**2)
|
|
assert cosh(acosh(x)) == x
|
|
assert cosh(atanh(x)) == 1/sqrt(1 - x**2)
|
|
assert cosh(acoth(x)) == x/(sqrt(x - 1) * sqrt(x + 1))
|
|
|
|
assert tanh(asinh(x)) == x/sqrt(1 + x**2)
|
|
assert tanh(acosh(x)) == sqrt(x - 1) * sqrt(x + 1) / x
|
|
assert tanh(atanh(x)) == x
|
|
assert tanh(acoth(x)) == 1/x
|
|
|
|
assert coth(asinh(x)) == sqrt(1 + x**2)/x
|
|
assert coth(acosh(x)) == x/(sqrt(x - 1) * sqrt(x + 1))
|
|
assert coth(atanh(x)) == 1/x
|
|
assert coth(acoth(x)) == x
|
|
|
|
assert csch(asinh(x)) == 1/x
|
|
assert csch(acosh(x)) == 1/(sqrt(x - 1) * sqrt(x + 1))
|
|
assert csch(atanh(x)) == sqrt(1 - x**2)/x
|
|
assert csch(acoth(x)) == sqrt(x - 1) * sqrt(x + 1)
|
|
|
|
assert sech(asinh(x)) == 1/sqrt(1 + x**2)
|
|
assert sech(acosh(x)) == 1/x
|
|
assert sech(atanh(x)) == sqrt(1 - x**2)
|
|
assert sech(acoth(x)) == sqrt(x - 1) * sqrt(x + 1)/x
|
|
|
|
|
|
def test_issue_4136():
|
|
assert cosh(asinh(Integer(3)/2)) == sqrt(Integer(13)/4)
|
|
|
|
|
|
def test_sinh_rewrite():
|
|
x = Symbol('x')
|
|
assert sinh(x).rewrite(exp) == (exp(x) - exp(-x))/2 \
|
|
== sinh(x).rewrite('tractable')
|
|
assert sinh(x).rewrite(cosh) == -I*cosh(x + I*pi/2)
|
|
tanh_half = tanh(S.Half*x)
|
|
assert sinh(x).rewrite(tanh) == 2*tanh_half/(1 - tanh_half**2)
|
|
coth_half = coth(S.Half*x)
|
|
assert sinh(x).rewrite(coth) == 2*coth_half/(coth_half**2 - 1)
|
|
|
|
|
|
def test_cosh_rewrite():
|
|
x = Symbol('x')
|
|
assert cosh(x).rewrite(exp) == (exp(x) + exp(-x))/2 \
|
|
== cosh(x).rewrite('tractable')
|
|
assert cosh(x).rewrite(sinh) == -I*sinh(x + I*pi/2)
|
|
tanh_half = tanh(S.Half*x)**2
|
|
assert cosh(x).rewrite(tanh) == (1 + tanh_half)/(1 - tanh_half)
|
|
coth_half = coth(S.Half*x)**2
|
|
assert cosh(x).rewrite(coth) == (coth_half + 1)/(coth_half - 1)
|
|
|
|
|
|
def test_tanh_rewrite():
|
|
x = Symbol('x')
|
|
assert tanh(x).rewrite(exp) == (exp(x) - exp(-x))/(exp(x) + exp(-x)) \
|
|
== tanh(x).rewrite('tractable')
|
|
assert tanh(x).rewrite(sinh) == I*sinh(x)/sinh(I*pi/2 - x)
|
|
assert tanh(x).rewrite(cosh) == I*cosh(I*pi/2 - x)/cosh(x)
|
|
assert tanh(x).rewrite(coth) == 1/coth(x)
|
|
|
|
|
|
def test_coth_rewrite():
|
|
x = Symbol('x')
|
|
assert coth(x).rewrite(exp) == (exp(x) + exp(-x))/(exp(x) - exp(-x)) \
|
|
== coth(x).rewrite('tractable')
|
|
assert coth(x).rewrite(sinh) == -I*sinh(I*pi/2 - x)/sinh(x)
|
|
assert coth(x).rewrite(cosh) == -I*cosh(x)/cosh(I*pi/2 - x)
|
|
assert coth(x).rewrite(tanh) == 1/tanh(x)
|
|
|
|
|
|
def test_csch_rewrite():
|
|
x = Symbol('x')
|
|
assert csch(x).rewrite(exp) == 1 / (exp(x)/2 - exp(-x)/2) \
|
|
== csch(x).rewrite('tractable')
|
|
assert csch(x).rewrite(cosh) == I/cosh(x + I*pi/2)
|
|
tanh_half = tanh(S.Half*x)
|
|
assert csch(x).rewrite(tanh) == (1 - tanh_half**2)/(2*tanh_half)
|
|
coth_half = coth(S.Half*x)
|
|
assert csch(x).rewrite(coth) == (coth_half**2 - 1)/(2*coth_half)
|
|
|
|
|
|
def test_sech_rewrite():
|
|
x = Symbol('x')
|
|
assert sech(x).rewrite(exp) == 1 / (exp(x)/2 + exp(-x)/2) \
|
|
== sech(x).rewrite('tractable')
|
|
assert sech(x).rewrite(sinh) == I/sinh(x + I*pi/2)
|
|
tanh_half = tanh(S.Half*x)**2
|
|
assert sech(x).rewrite(tanh) == (1 - tanh_half)/(1 + tanh_half)
|
|
coth_half = coth(S.Half*x)**2
|
|
assert sech(x).rewrite(coth) == (coth_half - 1)/(coth_half + 1)
|
|
|
|
|
|
def test_derivs():
|
|
x = Symbol('x')
|
|
assert coth(x).diff(x) == -sinh(x)**(-2)
|
|
assert sinh(x).diff(x) == cosh(x)
|
|
assert cosh(x).diff(x) == sinh(x)
|
|
assert tanh(x).diff(x) == -tanh(x)**2 + 1
|
|
assert csch(x).diff(x) == -coth(x)*csch(x)
|
|
assert sech(x).diff(x) == -tanh(x)*sech(x)
|
|
assert acoth(x).diff(x) == 1/(-x**2 + 1)
|
|
assert asinh(x).diff(x) == 1/sqrt(x**2 + 1)
|
|
assert acosh(x).diff(x) == 1/(sqrt(x - 1)*sqrt(x + 1))
|
|
assert acosh(x).diff(x) == acosh(x).rewrite(log).diff(x).together()
|
|
assert atanh(x).diff(x) == 1/(-x**2 + 1)
|
|
assert asech(x).diff(x) == -1/(x*sqrt(1 - x**2))
|
|
assert acsch(x).diff(x) == -1/(x**2*sqrt(1 + x**(-2)))
|
|
|
|
|
|
def test_sinh_expansion():
|
|
x, y = symbols('x,y')
|
|
assert sinh(x+y).expand(trig=True) == sinh(x)*cosh(y) + cosh(x)*sinh(y)
|
|
assert sinh(2*x).expand(trig=True) == 2*sinh(x)*cosh(x)
|
|
assert sinh(3*x).expand(trig=True).expand() == \
|
|
sinh(x)**3 + 3*sinh(x)*cosh(x)**2
|
|
|
|
|
|
def test_cosh_expansion():
|
|
x, y = symbols('x,y')
|
|
assert cosh(x+y).expand(trig=True) == cosh(x)*cosh(y) + sinh(x)*sinh(y)
|
|
assert cosh(2*x).expand(trig=True) == cosh(x)**2 + sinh(x)**2
|
|
assert cosh(3*x).expand(trig=True).expand() == \
|
|
3*sinh(x)**2*cosh(x) + cosh(x)**3
|
|
|
|
def test_cosh_positive():
|
|
# See issue 11721
|
|
# cosh(x) is positive for real values of x
|
|
k = symbols('k', real=True)
|
|
n = symbols('n', integer=True)
|
|
|
|
assert cosh(k, evaluate=False).is_positive is True
|
|
assert cosh(k + 2*n*pi*I, evaluate=False).is_positive is True
|
|
assert cosh(I*pi/4, evaluate=False).is_positive is True
|
|
assert cosh(3*I*pi/4, evaluate=False).is_positive is False
|
|
|
|
def test_cosh_nonnegative():
|
|
k = symbols('k', real=True)
|
|
n = symbols('n', integer=True)
|
|
|
|
assert cosh(k, evaluate=False).is_nonnegative is True
|
|
assert cosh(k + 2*n*pi*I, evaluate=False).is_nonnegative is True
|
|
assert cosh(I*pi/4, evaluate=False).is_nonnegative is True
|
|
assert cosh(3*I*pi/4, evaluate=False).is_nonnegative is False
|
|
assert cosh(S.Zero, evaluate=False).is_nonnegative is True
|
|
|
|
def test_real_assumptions():
|
|
z = Symbol('z', real=False)
|
|
assert sinh(z).is_real is None
|
|
assert cosh(z).is_real is None
|
|
assert tanh(z).is_real is None
|
|
assert sech(z).is_real is None
|
|
assert csch(z).is_real is None
|
|
assert coth(z).is_real is None
|
|
|
|
def test_sign_assumptions():
|
|
p = Symbol('p', positive=True)
|
|
n = Symbol('n', negative=True)
|
|
assert sinh(n).is_negative is True
|
|
assert sinh(p).is_positive is True
|
|
assert cosh(n).is_positive is True
|
|
assert cosh(p).is_positive is True
|
|
assert tanh(n).is_negative is True
|
|
assert tanh(p).is_positive is True
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assert csch(n).is_negative is True
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assert csch(p).is_positive is True
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assert sech(n).is_positive is True
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assert sech(p).is_positive is True
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assert coth(n).is_negative is True
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assert coth(p).is_positive is True
|