Exercise 27 Page 916

To solve the given equation, we will first use the Zero Product Property to solve for $\cos \theta .$ Then we will use the unit circle to find the exact values of $\theta$ that satisfy the equation.

Solving the Equation for $\cos \theta$

Let's start by using the Zero Product Property to solve the equation for $\cos \theta .$

Finding the Exact Values of $\theta$

We obtained two values for $\cos \theta .$ The cosine of an angle in standard position is the $x\text{-}$coordinate of the point of intersection $P$ of its terminal side and the unit circle.