# Change of variable in double integrals

1. Apr 18, 2007

### Zen

Nevermind (figured it out, sorry)

1. The problem statement, all variables and given/known data
Evaluate the integral $$\int{\int_T{e^\frac{y-x}{y+x} dA}}$$
where T is the triangle with vertices (0,0), (1,0), 0,1)

a) By transforming to polar coordiantes
b) By using the transformation u = y-x, v = y+x

2. Relevant equations
3. The attempt at a solution
http://folk.ntnu.no/bronner/m.mht

I know the differentiation in a) is wrong. (should be -2cos2x)

Last edited: Apr 18, 2007