Question

In what quadrant will θ terminate if a sin θ and cos θ are both negative?

Answer 1

Quadrant III

Since the cosine of the angle is positive, the sine of the angle must be negative and the terminal side of the angle lies in either Quadrant III or IV. If sin θ is negative, the terminal side of θ lies in either Quadrant III or IV.

Answer 2

Step-by-step explanation:

Both the sine and the cosine vary from positive to negative for angles that proceed around the unit circle. Those angles for which the sine and cosine are equal will be along the line y=x , which goes through the first and third quadrants.