This set of exercises will draw on the ideas presented in this section and your general math background.
Before the widespread use of calculators, values of the sine and cosine for selected angles in the interval $\left[0^{\circ}, 45^{\circ}\right]$ were given in tables. Why was there no need to list the sine and cosine for angles in the interval $\left(45^{\circ}, 90^{\circ}\right) ?$