00:03
All right, a little review with simplifying or verifying this identity.
00:11
The product of 1 minus sine square theta and 1 plus tangent square theta is equal to 1, and we want to verify that.
00:18
And all you're going to have to remember to do this is two of the pythagorean identities, right? so cosine squared theta plus sine squared theta equals 1.
00:33
That's pythagorean identity number 1.
00:36
You'll notice that if you just leave the cosine squared here and subtract the sign squared over, you'll get a match for that expression highlighted in green, right? notice that if i subtract the sign squared over, i get 1 minus sine squared theta.
00:55
So that means wherever you see 1 minus sine squared theta, you can just replace it with cosine squared theta.
01:03
That's the identity.
01:05
Similarly, let's look at 1 plus tangent squared theta.
01:12
That's also a pythagorean identity.
01:17
One plus tangent squared theta is actually equal to second squared theta...