Question -
Answer -
We have,
The points x =1 and x = −1 divide the real line in three disjoint intervalsi.e., 
In interval (−1, 1), it is observed that:
∴ f is strictly decreasing on 
In intervals
, it is observed that:
∴ f is strictly increasing on
Hence, function f is strictlyincreasing in interval I disjointfrom (−1, 1).
Hence, the given result is proved.