Question

For -180°<θ<0 , which of the primary trigonometric functions may have positive values?

Answer 1

cos theta = adj / hyp is positive (+/+)

Explanation:

In this open interval, the hypotenuse (radius) is always positive, whereas the adjacent side is positive and the opposite side negative.

in this interval:

sin theta = opp / hyp is neg (-/+)

cos theta = adj / hyp is positive (+/+)

tan theta = opp / adj = (-/+) : negative