# Question #e3d0f

##### 1 Answer

Dec 25, 2017

#### Explanation:

while you can use shell method, i think it's easier to rewrite y=x as a function of y and use disc method to rotate about the y-axis.

as a function of y, y=x becomes x=y.

using disc method, the volume of the solid is:

a and b are the upper and lower bounds of integration. in this problem,

r(y) is the distance between the function and the axis of rotation. in this problem,

plugging in: volume=