If cos(3α) = sin(α — 22°), where 3α < 90°, then what is the value of α ?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 28°
Given that
If cos(3α) = sin(α — 22°), where 3α < 90°,
According to the question
⇒ sin (90° - 3α) = sin(α — 22°)
⇒ 90° - 3α = α — 22°
⇒ 4α = 90° + 22° = 112°
⇒ α= 112°/4 = 28°