Find an equation for the surface obtained by rotating the parabola y = x^2 about the y-axis.

**Answer:** y = x^2 + z^2

## Explanation

Rotate y = x^2 around the y-axis

When rotated the traces parallel to the xz-plane are circles. So the equation should be that of a circle when y = k.

k = x^2

we just have to add a + z^2

y = x^2 + z^2