The expression is
.
(a)
\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
.
Consider the function is
.
Consider the function
to be continuous over the interval
.
Prove that the number
exists between
and
.

Substitute
in the above function.

Substitute
in the above function.

Thus,
.
Then according to intermediate value theorem, there exist at least one root between
and
such that
.
\
(b)
\Consider
be the root exist between
and
.
Then
.

Using calculator the value of
is
.
Therefore the interval is considered as
.
Interval of the function containing the root is
.
\
Interval of the function containing the root is
.