Question

How do you find the exact functional value cos(60˚+45˚) using the cosine sum or difference identity?

Answer 1

`(sqrt6-sqrt2)/4`

Explanation:

`cos(60^@+45^@) = cos(60^@)cos(45^@)-sin(60^@)sin(45^@)`

`= (sqrt3/2)(sqrt2/2)-(1/2)(sqrt2/2)`

`= (sqrt6-sqrt2)/4`