Question

For what value of x is sin x = cos 19°, where 0°< x < 90°? A. 38° B. 71° C. 26° D. 19°

Answer 1

B

Explanation:

using the cofunction identity

• sin (90 - x) = cosx / cos(90 - x) = sinx, hence

cos 19° = sin(90 - 19)° = sin 71°

Answer 2

B

Explanation:

using the cofunction identity

• sin (90 - x) = cosx / cos(90 - x) = sinx, hence

cos 19° = sin(90 - 19)° = sin 71°