00:02
Okay, so i want to establish the identity.
00:06
Either side you could work with, i mean, they're both equally complicated.
00:10
What you can't do is cross -multify.
00:12
So i'm going to work with the left just because out of habit i tend to work with the left.
00:18
And i am going to multiply the left by a form of one, one minus cosine over one minus cosine.
00:27
And my thinking when i'm doing that is that i want to get what's going to result in my denominator.
00:34
Which is 1 minus cosine squared.
00:38
Okay? on top, i'm going to leave it just like this.
00:44
When you're doing identities, you always want to keep your eye on the prize.
00:47
You want to look at where you're going.
00:50
And if i look at that right side, that right side has a 1 minus cosine in the numerator...