Step 1 :

Definition :

The derivative of a function f at a number a, denoted by $\"\"$ , is

$\"\"$ if this limit exists.

Step 2 :

The function is $\"\"$ .

Find $\"\"$ :

$\"\"$

Find $\"\"$ :

$\"\"$

The derivative of a function.

$\"\"$

Substitute the limit.

$\"\"$

Substitute $\"\"$ in above equation.

$\"\"$

Solution :

$\"\"$