Make the given changes in the indicated examples of this section and then solve the resulting problems.

In Example 7, change the − to + and then find θ.

Data from Example 7

Given that cos θ = −0.1298, find θ for 0° ≤ θ < 360°.
Because cosθ is negative, θ is either a second-quadrant angle or a third-quadrant angle. Using 0.1298, the calculator tells us that the reference angle is 82.54°. For the second-quadrant angle, we subtract 82.54° from 180° to get 97.46°. For the third-quadrant angle, we add 82.54° to 180° to get 262.54°. See Fig. 8.14. Therefore, the two solutions are 97.46° and 262.54°.