Question

If sin θ = cos (θ – 45°), where θ – 45° are acute angles, find the degree measure of θ

Answer 1

Sin θ = cos (θ – 45°)

Cos θ = cos (90 – θ)

Cos (θ – 45°) = sin (90° - (θ – 45°)) = sin (90 – θ + 45°)

Sin θ(135 – θ)

θ = 135 – θ

2θ = 135

∴ θ = 135°/2