A lamina occupies the part of the disk in the first quadrant and the density at each point is given by the function .
A. What is the total mass?
B. What is the moment about the x-axis?
C. What is the moment about the y-axis?
D. Where is the center of mass? (, )
E. What is the moment of inertia about the origin?

i started this problem using polar coordinates. the integral of 0 to 2pi and the integral of 0 to 1 of 5r^3 the answer i got was 5pi/2 which isn't correct. How do i do this?