Once you have established limits of integration on your variables and have
a integrand and the right set of differentials, you are ready to start integrating.
You are then on your own.
Exercise 31.8 Determine the moments of inertia of bodies with the
shape of the cone and ellipsoid above about the z axis. Assume that the mass densities
are constant throughout the bodies. (The moment of inertia of a body is the integral
of its density multiplied by the square of the distance of the volume element
to the z axis. However, it is always expressed as a function not of the density,
but of the mass of the body. You must therefore take the ratio of the integral
determining the moment of inertia, and that determining the mass to get the relation
between the two.)
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