Find all angles θ between 0° and 180° satisfying the given equation. Round your answer to one decimal place. (Enter your answers as a comma-separated list.) cos(θ) = − 3/5

Question

Hello ! I know how to figure out the answer when the given fraction is positive, but is it any different with negative numbers ? I got 126.9, 53.1 but apparently I got it wrong.

Answer 1

It has to be in the 2nd quadrant because all trig functions are positive in the 1st quadrant.

Remember: All Students Take Calculus or Add Sugar to Coffee

The inverse cosine of 3/5 returns an angle of 53.1.

In the 2nd quadrant that is 126.9