Participation Activity \#7 This is similar to Try It \#2c in the OpenStax text. Evaluate \( \cos ^{-1}(-1) \) Enter the exact answer.

The angle whose cosine is -1 is \( \pi \) radians (or 180 degrees). This is because the cosine function reaches -1 at \( \pi \), which is located on the negative x-axis of the unit circle. Therefore, \( \cos^{-1}(-1) = \pi \). To illustrate the concept visually, think about the unit circle: as you traverse the circle counterclockwise starting from (1,0), you reach the point (-1,0) at exactly \( \pi \) radians. So, there you have it, the inverse cosine of -1 lands you right on the opposite side of the circle!