Question

find the exact value of cos(-π). cos(-π) =

Explanation:

Step1: Use cosine even function property

The cosine function is even, so $\cos(-\theta) = \cos(\theta)$. Thus, $\cos(-\pi) = \cos(\pi)$.

Step2: Recall cosine of π

We know from the unit circle that $\cos(\pi) = -1$.

Answer:

-1