The function is
.
The function is continuous in the interval
.
Derivative of
is
, which is negative in the interval
.
So the function is one-to-one and is strictly monotonic.
\Therefore, inverse exists.
\From theorem 5.9 :
.
Equate
to
.

By trial and error process we will get
.
Thus, 
.
.
Substitute
in above expression.
.
Consider
.

Substitute
in
.
.
.