Originally Posted by

**juicysharpie** Hi,

Thanks for your help.

I did use 4cos theta as the upper boundary, and 4 as a lower boundary when integrating with respect to r. I also used pi/2 and 0 as the upper and lower boundaries, respectively when integrating with respect to theta. I got the wrong answer though.. $\displaystyle \int_0^\frac{\pi}{2} \ \int_0^{4 \cos \theta} \ r^2 \cos \theta dr d \theta $. What I got was 64pi-256/12, but the answer isn't right. Are my boundaries incorrect?

Thanks again.