# How do you evaluate cos(cos^-1(1.1))?

$\cos \left({\cos}^{-} 1 \left(1.1\right)\right)$ cannot be evaluated
$y = {\cos}^{-} 1 \left(x\right)$ is defined as the number $y$ for which $\cos y = x$.
As the range of $\cos x$ is $\left[- 1 , 1\right]$ there is no number for which $\cos y = 1.1$
Therefore $\cos \left({\cos}^{-} 1 \left(1.1\right)\right)$ is not defined.