Question

Which pair are equal trig values? A) tan 45° and sin 45° Eliminate B) sin 40° and sin 50° C) sin 36° and cos 54° D) cos 65° and sin 65°

Answer 1

C

Explanation:

note that sin x = cos(90 - x ) ← Cofunction identity

If x = 36 then 90 - x = 90 - 36 = 54

Hence sin 36° = cos 54° → C