$\phi$(

**r**)=$\exp[x^2+y^2] * sin(x^2 - y^2)$

And switch to polar coordinates. But every time I do so I get trig functions sandwiched together. The $x^2 + y^2$ in the exp is simple as it's just r^2. However, the $x^2 - y^2$ in the sin function becomes a mess when I substitute in the $r^2sin^2(\theta)*r^2cos^2(\theta)$ in there. Is there a way to do this and get a more simple answer?

Thanks!