Status: New
Owner: ----
Labels: Type-Defect Priority-Medium

New issue 3952 by omar.ant...@gmail.com: Sympy cannot compute the integral of sqrt(tan(x))
http://code.google.com/p/sympy/issues/detail?id=3952

Sympy gives up on integrate(sqrt(tan(x)),x) and returns it unevaluated.

Mathematica answers (in Sympy notation):

-2*atan(1-sqrt(2)*sqrt(tan(x))) + 2*atan(sqrt(2)*sqrt(tan(x))+1) + log(tan(x)-sqrt(2)*sqrt(tan(x))+1) - log(tan(x)+sqrt(2)*sqrt(tan(x))+1))/(2*sqrt(2))

Trying to check Mathematica's answer in Sympy, by doing
  simplify(diff(that_thing,x) - sqrt(tan(x)))
does not give 0, but plotting the difference shows it is zero from 0 to pi/2.

Maxima gives the answer (again, in Sympy notation):

2*(-log(tan(x)+sqrt(2)*sqrt(tan(x))+1)/2**(S(5)/2)
        +log(tan(x)-sqrt(2)*sqrt(tan(x))+1)/2**(S(5)/2)
        +atan((2*sqrt(tan(x))+sqrt(2))/sqrt(2))/2**(S(3)/2)
        +atan((2*sqrt(tan(x))-sqrt(2))/sqrt(2))/2**(S(3)/2))

and computing in Sympy
  simplify(diff(that_thing,x) - sqrt(tan(x)))
does produce 0.


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