Chapter 3 - Radian Measure and the Unit Circle - Section 3.3 The Unit Circle and Circular Functions - 3.3 Exercises - Page 123: 5

1

An angle of $\frac{\pi}{4}$ radians intersects the unit circle at the point $(\frac{\sqrt 2}{2},\frac{\sqrt 2}{2}$) as we saw in the solution of excercise 1. Because, $\tan s=\frac{y}{x}$ $\tan \frac{\pi}{4}=\frac{\frac{\sqrt 2}{2}}{\frac{\sqrt 2}{2}}=1$.