# Calculus Disk/Washer method: How did we arrive to this answer?

Let R be the region bounded by the following curves. Use the disk or washer method to find the volume of the solid generated when R is revolved about he y-axis.

y=x, y=3x, y=12

Answer: \int_0^16 15/16 π$y^2$

This is setting up the integral only. 0, 16 were given in the graph. I followed the formula but I'm lost. Anyone can help so I can compare to my work and see what I've missed?

• Nobody can check your attempt if you don't post it. Anyway, good to know that you have solved it, but I don't think there is any point in keeping your question around. – user21820 Sep 22 '18 at 11:41