Question

If sin 3A = cos 6A, then ∠A = ?

Answer 1

sin 3A = cos 6A     .....[Given]

∴ sin 3A = sin(90° – 6A)  .....[∵ cos θ = sin(90° – θ)]

∴ 3A = 90° – 6A

∴ 3A + 6A = 90°

∴ 9A = 90°

∴ A = `(90^circ)/9`

∴ A = 10°