Solution
= Solution
Differentiability at $x$ means that the <limit>
$$
f\prime(x)=\lim_{h\to0}\frac{f(x+h)-f(x)}h
$$
exists as a finite real number.
= Solution
Differentiability at $x$ means that the <limit>
$$
f\prime(x)=\lim_{h\to0}\frac{f(x+h)-f(x)}h
$$
exists as a finite real number.