00:01
In this problem, we are going to be verifying this identity that we see here.
00:06
Let's start off with the left -hand side and begin manipulating this left -hand side until we get to the right -hand side.
00:13
So the left -hand side is sine alpha plus beta, divided by cosine alpha times cosine of beta.
00:24
Our very first step in proving this identity is to use the identity for the addition formula of sine, which is this formula we see here.
00:34
We can write that the numerator is equal to sine of alpha times cosine of beta plus that we see here converts to a plus here so we'll go plus cosine of alpha times sine of beta and then the whole thing is being divided by cosine of alpha times cosine of alpha times cosine of beta.
01:03
In our next step we're going to break up this into two different fractions, both divide by cosine alpha, cosine beta.
01:12
So cosine alpha, cosine beta goes here, and then once again, cosine alpha, cosine beta.
01:22
So this divides first into sine alpha times cosine beta...