Final answer:
The lower bound of the sine function is -1 and the upper bound is 1.
Step-by-step explanation:
The lower bound of the sine function is -1 and the upper bound is 1. This means that the y-values of the sine function will always be between -1 and 1.
For example, when the angle is 0, the sine value is 0, and when the angle is 90 degrees, the sine value is 1.