The function is , and .

The function is continuous in the interval . 

The function is .

.

Derivative is always positive, so it is always increasing on the interval .

So the function is one-to-one function and is strictly monotonic.

Find .

From theorem 5.9 :

.

Equate to 6.

By trial and error process we will get .

Thus,

.

.

Substitute in above expression.

.

Consider .

Substititue in .

.

.