cos(45)+cos(30)

<-- Enter special trig expression or identity

Using the Sum to Product Formula for Trig, Calculate Cos(45°) + Cos(30°)

The Sum to Product Formula Formula states the following:
Cos(u) + Cos(v) = 2cos(a)cos(b)
a and b are defined below:
a =u + v
2

a =45 + 30
2

a =75
2

a = 37.5

b =u - v
2

b =45 - 30
2

b =15
2

b = 7.5

With a = 37.5° and b = 7.5°, we have
cos(45) + sin(30) = 2cos(37.5)cos(7.5)
cos(45) + sin(30) = 2(1)(1)
cos(45 + 30) = 2