I have to solve this exercise I will describe but I am facing some problems.
$\int\int_\tau(x+y)\;dx\;dy$ where $(x-2)^2 + y^2 \leq 4$ and $y\geq0$
So I am trying to find this integration inside half of a circle.
$\theta$ is from 0 to $\pi/2$ and $r\leq 4 \cos \theta$
$\int_0^{\pi/2}\int_{4\cos\theta}^0r^2(\cos \theta+\sin\theta)\;dr\;d\theta$
Something is wrong with the plane of integration cause I am getting wierd results.