Integral that represents the volume of the solid obtained by rotating an ellipse about a line.

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I was given this question to answer:

x2+ y2 = 4 rotates about y = 2

I know how to find volume when I have 2 functions and their the outer and inner radius (distances from the rotation axis). What is the approach to this question? Thank you!

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The approach is very similar. For example, if we use shell method,

Shell width at $y$ (distance from x-axis) is $2 \sqrt{4-y^2}$.

Radial distance of the shell from $y = 2$ is $(2 - y)$ where $ - 2 \leq y \leq 2$.

Now, can you you complete the working?