# How do you evaluate cos^-1(1)?

##### 1 Answer
Apr 26, 2016

$2 n \pi , n = 0. \pm 1 , \pm 2 , \pm 3. . .$

#### Explanation:

The principal values of ${\cos}^{- 1} \left(1\right) \in \left[0 , 2 \pi\right]$ are 0 and $2 \pi$

So, the general value = .$2 n \pi , n = 0. \pm 1 , \pm 2 , \pm 3. .$