Question

find partial derivatives of
tan^(-1)(2xy/(x^2-y^2))

Answer 1

\[ u = \tan^{-1} \left( \frac{2xy}{x^2-y^2}\right ) \]
for x derivatie,
http://www.wolframalpha.com/input/?i=D%5BArcTan%5B2xy%2F%28x%5E2-y%5E2%29%5D%2C+x%5D
or y derivative
http://www.wolframalpha.com/input/?i=D%5BArcTan%5B2xy%2F%28x%5E2-y%5E2%29%5D%2C+y%5D