Please help me with this question. Thank you!

A sphere of radius rhosub0 centered at the origin has cylindrical coordinate equation r^2 + z^2 = (rhosub0)^2; and the cone with spherical coordinates phi=phisub0 has cylindrical coordinate equation z=r*cotphisub0.

Using the information and a triple integral in cylindrical coordinates , show that the volume V of the spherical wedge solid bounded above by a sphere rho = phosub0, below by a cone phi=phisub0 and on the side theta=thetasub1 and theta=thetasub2 (thetasub1 < thetasub2) is

V = 1/3 * (phosub0)^3 *(1-cosphisub0) (thetasub2-thetasub1).
Remark : phisub0 is from 0 to pi/2