Question #3089d

1 Answer
Jan 19, 2018

If you draw out the sine, cosine, and tangent graphs, then you can construct a table showing of which quadrants they are positive or negative.

In the first quadrant all sine cosine tangent are positive. In the second, only sine is positive; the rest are negative. In the third, tangent is positive, and in the fourth, cosine is positive.

Based on this information you can solve your problem:
The quadrants of which cosine theta is positive is quadrants 1 and 4. The quadrants of which sine theta is negative is quadrants 3 and 4. They share a common quadrant: quadrant 4.

Therefore, theta is in quadrant 4.