Status: New
Owner: ----
Labels: Type-Defect Priority-Medium
New issue 3058 by [email protected]: solve cannot handle mixed trig functions
http://code.google.com/p/sympy/issues/detail?id=3058
Trying to solve the equation:
2*sin(x) = cos(x)
By hand:
2*sin(x) = cos(x)
2*sin(x)/cos(x) = 1
sin(x)/cos(x) = 1/2
tan(x) = 1/2
x = atan(1/2)
By SymPy:
from sympy import *
x = Symbol('x')
solve(2*sin(x)-cos(x),x)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "C:\Python27\lib\site-packages\sympy\solvers\solvers.py", line 484,
in solve
solution = _solve(f, *symbols, **flags)
File "C:\Python27\lib\site-packages\sympy\solvers\solvers.py", line 700,
in _solve
soln = tsolve(f_num, symbol)
File "C:\Python27\lib\site-packages\sympy\solvers\solvers.py", line 1143,
in tsolve
"(tsolve: at least one Function expected at this point")
NotImplementedError: Unable to solve the equation(tsolve: at least one
Function expected at this point
solve(2*sin(x)/cos(x)-1,x)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "C:\Python27\lib\site-packages\sympy\solvers\solvers.py", line 484,
in solve
solution = _solve(f, *symbols, **flags)
File "C:\Python27\lib\site-packages\sympy\solvers\solvers.py", line 565,
in _solve
strategy = guess_solve_strategy(f, symbol)
File "C:\Python27\lib\site-packages\sympy\solvers\solvers.py", line 207,
in guess_solve_strategy
return max([guess_solve_strategy(i, symbol) for i in expr.args])
File "C:\Python27\lib\site-packages\sympy\solvers\solvers.py", line 220,
in guess_solve_strategy
raise NotImplementedError
NotImplementedError
solve(sin(x)/cos(x)-S(1)/2,x)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "C:\Python27\lib\site-packages\sympy\solvers\solvers.py", line 484,
in solve
solution = _solve(f, *symbols, **flags)
File "C:\Python27\lib\site-packages\sympy\solvers\solvers.py", line 565,
in _solve
strategy = guess_solve_strategy(f, symbol)
File "C:\Python27\lib\site-packages\sympy\solvers\solvers.py", line 207,
in guess_solve_strategy
return max([guess_solve_strategy(i, symbol) for i in expr.args])
File "C:\Python27\lib\site-packages\sympy\solvers\solvers.py", line 220,
in guess_solve_strategy
raise NotImplementedError
NotImplementedError
solve(tan(x)-S(1)/2,x)
[atan(1/2)]
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