Question

How do you rewrite `cos83cos53+sin83sin53` as a function of a single angle and then evaluate?

Answer 1

By the difference formula `cos(A - B) = cosAcosB + sinAsinB`:

`=cos(83 - 53)`

`=cos(30)`

`=sqrt(3)/2`

Hopefully this helps!

Answer 2

The answer is `sqrt3/2`

Explanation:

`cos(a-b)=cosacosb+sinasinb`
So, `cos83cos53+sin83sin53=cos(83-53)=cos30=sqrt3/2`