Question

Write the expression in terms of cosine. Please help.

Answer 1

cos60°

Explanation:

Using the cofunction identity

sinx° = cos(90 - x)°

sin30° = cos(90 - 30)° = cos60°

Answer 2

I would assume that they want a cosine value that would give the same answer. sin(30°) is equal to 1/2

Therefore cos(×) = 1/2

x = arccos(1/2)

x=60

cos(60°)