Question

Which pair of trigonometric values is equivalent?

1) cos 38°, sin 38°
2) cos 65°, sin 25°
3) sin 71°, sin 19°
4) cos 113°, cos 67°

Answer 1

The pair of trigonometric values that is equivalent is cos 38° and sin 52°. Hence the correct answer is option 1

Step-by-step explanation:

The pair of trigonometric values that is equivalent is cos 38° and sin 52°.

To see why this is true, let's review the unit circle. At 38°, the reference angle is 52°, which is the same as the angle for sin. Since cos is the adjacent side divided by the hypotenuse, and sin is the opposite side divided by the hypotenuse, the values for cos 38° and sin 52° are equal.

Therefore, option 1) cos 38° and sin 38° is the correct answer.