1. The problem statement, all variables and given/known data Evaluate the integral ∫∫sin(x+y)/(x+y) dydx over the region D whereD⊆R2 is bounded by x+y=1, x+y=2, x-axis, and y-axis. 2. Relevant equations 3. The attempt at a solution I think that I need to use a change of variables but can not find any change of variables that work. One thing I thought would work is using u = sin(x+y) and v = (x+y) but finding the jacobian doesn't work with the u transformation. This leads me to think I might need to do a taylor expansion instead. Any help with a recommended change of variables or a step in the right way would be appreciated.