(a) Given:
=
……….(i)
Now
or
or
Therefore, we have sub-intervals are and
For interval taking (say), from eq. (i),
> 0
Therefore, is strictly increasing in
For interval taking (say), from eq. (i),
< 0
Therefore, is strictly decreasing in
For interval taking (say), from eq. (i),
> 0
Therefore, is strictly increasing in
Hence, (a) is strictly increasing in and
(b) is strictly decreasing in