for the region bounded by the curves y=0 and y= +squareroot(9-x^2) (only the positive portion of that function, i think thats why there is a plus sign in front of the squareroot) find:
1. its area
2. M sub x
3. M sub y
4. X bar (x with a bar on top of it)
5. Y bar (y with a bar on top of it)
6. the centroid
i have no idea how to do this problem...