Question

If cos (45° + x) = sin 30°, then x = ?

Answer 1

cos (45° + x) = sin 30°   ...[Given]

∴ cos (45° + x) = sin (90° – 60°)

∴ cos (45° + x) = cos 60°   ...[∵ sin (90° – θ) = cos θ]

∴ 45° + x = 60°

∴ x = 60° – 45°

∴ x = 15°