Step 1:

The function is .

Definition of derivative using limit concept

Substitute in above expression.

.

Step 2:

The domain of 

The Domain of a function is all values of , those makes the function mathematically correct.

Denominator of the function should not be zero.

Hence,

The domain of function is .

Step 3:

The domain of

Denominator of the function should not be zero.

Hence,

The domain of function is .

Solution:

.

The domain of function is .

The domain of function is .