### Home > CALC > Chapter 9 > Lesson 9.1.1 > Problem 9-10

9-10.

Start by determining the points of intersection. The *x*-values of the points of intersection will be the bounds of your integral (this is rotation about the *x*-axis, so the width of the washers is *dx*).

The general formula for the washer method is:

Which function is the outer radius *R* and which function is the inner radius *r*?