If sin 3A = cos (A — 26°), where 3A is an acute angle, find the value of A.

Question

Philoid · Accepted Answer

We are given that: sin 3A = cos (A - 26°)

∴We can rewrite it as: cos (90° - 3A) = cos (A - 26°)

On comparing both sides, we get,

90° - 3A = A - 26°

⇒ A + 3A = 90° + 26°

⇒ 4A = 116°

⇒ A = 29°