## Calculus (3rd Edition)

$$\lim_{x\to 0}f(x)=1.$$
Since $\lim_{x\to 0}\cos x =\lim_{x\to 0}1=1$ and $\cos x\leq f(x)\leq 1$, then by the squeeze theorem, we have, $$\lim_{x\to 0}f(x)=1.$$