The function is .

Find .

Theorem 7: 

If is a one to one differentiable function with inverse function and then the inverse function is

differentiable at and .

Find .

Equate the function to .

.

From the fundamental theorem of calculus part 2 definition,

, where is the antiderivative of the function .

Here .

Above expression is true for .

Therefore, then .

From the fundamental theorem of calculus part 1 definition,

is continuous on then .

Here then .

Therefore, .

Substitute in.

.

.