32 lines
1.1 KiB
Python
32 lines
1.1 KiB
Python
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from sympy.core.numbers import I
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from sympy.core.symbol import symbols
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from sympy.functions.elementary.exponential import exp
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from sympy.functions.elementary.trigonometric import (cos, cot, sin)
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from sympy.testing.pytest import _both_exp_pow
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x, y, z, n = symbols('x,y,z,n')
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@_both_exp_pow
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def test_has():
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assert cot(x).has(x)
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assert cot(x).has(cot)
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assert not cot(x).has(sin)
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assert sin(x).has(x)
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assert sin(x).has(sin)
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assert not sin(x).has(cot)
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assert exp(x).has(exp)
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@_both_exp_pow
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def test_sin_exp_rewrite():
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assert sin(x).rewrite(sin, exp) == -I/2*(exp(I*x) - exp(-I*x))
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assert sin(x).rewrite(sin, exp).rewrite(exp, sin) == sin(x)
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assert cos(x).rewrite(cos, exp).rewrite(exp, cos) == cos(x)
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assert (sin(5*y) - sin(
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2*x)).rewrite(sin, exp).rewrite(exp, sin) == sin(5*y) - sin(2*x)
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assert sin(x + y).rewrite(sin, exp).rewrite(exp, sin) == sin(x + y)
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assert cos(x + y).rewrite(cos, exp).rewrite(exp, cos) == cos(x + y)
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# This next test currently passes... not clear whether it should or not?
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assert cos(x).rewrite(cos, exp).rewrite(exp, sin) == cos(x)
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