Question

mostrar pela definição que se f (x)=18=>f (x)=0

Answer 1

$f'(x)= \lim_{h \to 0} \frac{f(x+h)-f(x)}{h} \\\\f'(x)= \lim_{h \to 0} \frac{18-18}{h} \\\\f'(x)= \lim_{h \to 0} \frac{0}{h} \\\\f'(x)=0* \lim_{h \to 0} \frac{1}{h} =0$