Determine the volume bounded by the parabolic cylinder $z=x^2$ and the planes $y=0$ and $y+z=4$.
My work. I am not sure if I have the correct limits for this question. I used
$x = -\sqrt{z},\dots, \sqrt{z}$,
$y= 0,\dots, 4-z$,
$z=0,\dots,4$.
It seems too easy, should I be using polars?


Yes, the limits are correct, the volume is given by the following iterated integral $$\int_{z=0}^{4}\left(\int_{x=-\sqrt{z}}^{\sqrt{z}}\left(\int_{y=0}^{4-z} dy\right) dx\right) dz.$$ Can you take it from here? Cartesian coordinates seems to be fine here.