00:01
We're asked to verify the identity cosine 2 u over 1 minus sine 2 u equals 1 plus tangent u over 1 minus tangent u.
00:08
So we're going to be looking at the right side of this identity, and we're going to try to turn the right side into the left side so that we can verify this.
00:19
So our first step in verifying this is going to be to turn the tangent u into sine u over cosine u.
00:27
And we're going to do the same thing on the bottom.
00:31
Sorry, that looks like an o.
00:36
So that is 1 minus sine u over cosine u.
00:41
So now we're going to turn the 1 into cosine u over cosine u.
00:47
And then once we combine the fraction, i'm skipping a step there, this becomes cosine plus sine u over cosine u.
00:56
And we're going to do the same thing on the bottom, turn this 1 into cosine u over cosine u, and then that minus sine u all over cosine u...