Question

Since sin 3A = cos(A – 26°), where 3A is an acute angle, find the value at A.

Answer 1

We are given that sin 3A = cos (A – 26°) … (1)

Since sin 3A = cos(90° – 3A) we can write (1) as

cos(90° – 3A) = cos(A – 26°)

Since 90° – 3A and A – 26° are both acute angles.

90° – 3A = A – 26°

Which gives A = 29°