Question

Find a angles, 0°≤ theta < 360°, that solve the following equation.cos theta = -1

Answer 1

`\cos \theta=-1`

to solve the equation apply the inverse function of the cos on both sides

`\begin{gathered} \cos ^(-1)(\cos \theta)=\cos ^(-1)(-1) \\ \theta=\cos ^(-1)(-1) \\ \theta=180 \end{gathered}`

Using the unit circle there is only one solution over the given interval.

Answer

`\theta=180`