\
The expression is
,
.
Intermediate value theorem :
\The function
is continuous on the closed interval
, let
be the number between
and
, where
then exist a number
in
such that
.
Prove that the number
exists between
and
such that
.
Consider the function is
.
Substitute
in the function.

.
Substitute
in the function.

Thus, 
The function
is continuous since it is a polynomial.
The intermediate value theorem says there is
between
and
such that
.
\
The value
exists between
and
such that
.