The function is
and
.
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
.
By using inspection method find value of
.
Substitute
in above equation.

is clearly root of the equation.
Therefore
then
.
Consider
.
Apply derivative on each side with respect to
.


From theorem 7,
.
Substitute
in above equation.


.
.