[ksack001]

so here I am faced with this problem.
For a particle on a sphere, calculate the angle that the angular momentum vector makes with the z-axis when the system is in the state represented by the spherical harmonic .  The angle should be expressed in terms of l and ml.


How would I do this or begin to do this? I belive it would be dependent on theta as this is the angle from the z axis. but how would I come up with an expression or equation to plug in theta and get an angle?