# Setting up an integral for surface area

## Homework Statement

Set up an integral that represents the area of the surface generated when the region is bounded by x + y2 = 1 and the y-axis, then rotated about the y-axis. All in one-variable.

## Homework Equations

SA = 2pi $$\int xds$$
possible x2 + y2 = r2

## The Attempt at a Solution

I tried to set up an integral as a circle and somehow ended up getting 2pi$$\int(r/2)(2pi r) dr$$

When I picture it, it would be a sphere with a radius of 1. Still don't truly understand on how to make a integral to show it

would one possible answer be: 4pi$$\int(-y^2 + 1)\sqrt{1 + 4y^2}dy$$