Question

For what value of theta does sin 2theta = cos(theta+30)? Show steps

Answer 1

Answer: Ф = 20

Step-by-step explanation:

sin2Ф = cos (Ф+ 30 )

if sinα = cosβ , then α and β are complementary ,that is they add up to be $90^{0}$.

Therefore : 2Ф + Ф + 30 = 90

3Ф + 30 = 90

3Ф         = 90 - 30

3Ф        = 60

Ф          = 20