Derive these identities using the addition or subtraction formulas for sine or cosine: sinacosb=(sin(a+b)+sin(a-b))/2

The work is in the explanation.

Step-by-step explanation:

The sine addition identity is:

.

The sine difference identity is:

.

The cosine addition identity is:

.

The cosine difference identity is:

.

We need to find a way to put some or all of these together to get:

.

So I do notice on the right hand side the and the .

Let's start there then.

There is a plus sign in between them so let's add those together:

There are two pairs of like terms. I will gather them together so you can see it more clearly:

So this implies:

Divide both sides by 2:

By the symmetric property we can write:

answer: 2530

hope this

i'm assuming that it's c.)   volcanoes built the mountains and earthquakes tore them down.