Question

Find the derivative of f(x) = 3x at x = 2

Answer 1

We have,

f(x) = 3x

$\because f^{\prime }\left(a\right)=li{m}_{h\to 0}\frac{f(a+h)-f\left(a\right)}{h}$

$\because f^{\prime }\left(a\right)=li{m}_{h\to 0}\frac{f(2+h)-f\left(2\right)}{h}$

$={lim}_{h\to 0}\frac{3(2+h)-6}{h}$

$={lim}_{h\to 0}\frac{3h}{h}$

$={lim}_{h\to 0}3$