why does the unit circle with center in (1,0) have period $\displaystyle -\frac{\pi}{2} , \frac{\pi}{2}$ and not $\displaystyle 0, 2\pi$ ?
im just suppose to solve it using polar cordinates. thats all. And im suppose to integrate over the circle $\displaystyle (x-1)^2+y^2\leq 1$ so i guess they mean the whole circle. the only thing is that it has its center at (1,0) and not (0,0).
$\displaystyle (r\cos(\theta)-1)^2 + r^2\sin^2(\theta) \leq 1 \Rightarrow r \leq 2\cos(\theta)$, so thats for r, but I cant see how they get to $\displaystyle -\pi/2 \leq \theta \leq \pi/2$