. In Worksheet 2 you were asked to evaluate the triple integral ∭ E
​
zdV, where E is bounded by the cylinder y 2
+z 2
=9 and the planes x=0,z=0 and y=3x. You may have used the projection of E in the xy-plane to do the integration. If so, integrate using the projection of E in the yz-plane, which is a quarter of a disk of radius 3, which can be parametrized using polar coordinates in the yz-plane. Calculate the integral using the new limits.