The integral is
.
Definition of an improper integral :
\If
exists for every number
, then
provoded this limit exists (as a finite number).

Consider
.
Let
.
Differentiate on each side with respect to
.

Boundaries : from
to
.
Substitute corresponding values in equation
.

Power rule of integral :
.

.
Since
(finite value), the integral is convergent.
The integral is convergent and the value is
.