## Thomas' Calculus 13th Edition

The answer is Yes, because if we know $\lim_{x\to c}f(x)$ exists, we know $\lim_{x\to c}f(x)=\lim_{x\to c^+}f(x)=\lim_{x\to c^-}f(x)$ and we can use $\lim_{x\to c^+}f(x)$ to obtain the others.