00:01
Okay, so we want to verify our colon identity.
00:06
So let's start, let's see.
00:07
So here we have the sum in our denominator, and here we have the product of sign and cosine.
00:13
So let's start with our left hand side.
00:19
Or actually, let's start with our right hand side.
00:21
We can split up our fraction into two fractions.
00:24
So this is going to give us cosine of us over sine of us and cosine of s, and then minus sine of s over sine of s and cosine of us.
00:39
So we see that this simplifies into a 1 over sine of s.
00:48
And then we have minus 1 over cosine of s.
00:56
Okay, but we want to write our denominator as a sum...