00:01
Okay, so we have, we're defining our scalar product on a sphere by this integral.
00:08
And we're going to find these three functions on the sphere.
00:11
If we think in terms of our usual spherical coordinates, this one is, all right.
00:43
So to derive the orthogonality integrals, we just have to do a couple of these.
00:49
So for instance, all right.
01:28
And i'll just point out right now that this right here, that combination is one half the sine of 2 phi, and when i integrate that from 0 to 2 pi, it's 0, because we're integrating sine 2 phi over actually two full periods.
01:57
So now we got to find the value of c, so let's calculate this, and that's all we got, okay? so the first factor, the d phi integral, just gives us 2 pi c squared.
02:42
And then this, we'll make a substitution, u is cos theta.
02:53
So du is minus sine theta d theta.
02:57
But now we're going to integrate from 1 to minus 1.
03:03
So minus 1 to 1, because the minus sign.
03:06
And we get u squared du...