Question

Hi can someone please help me? If sin2A=cos 3A find the value of A. Can you please explain in full detail how you arrived at your answer? Also Find the exact value of (sec30)^2. Will I need to use a calculator in order to solve this prob?

Answer 1

Sin (x) = Cos (90 - x)
sin(2A) = cos (90 - 2A)
=cos (3A)
90 - 2A = 3A
5A=90
A=18