# What is the smallest value of y=cos x?

Apr 15, 2018

$- 1$

#### Explanation:

We know that $\text{the Domain of cosine}$ is $\mathbb{R}$ ,but

$\text{the Range of cosine}$ is $\left[- 1 , 1\right]$

i.e. $- 1 \le \cos x \le 1$

It is clear that ,the smallest value of $y = \cos x$ is: $- 1$