The function is .
Consider .
Derivative on each side by .
Apply the power rule of derivative :.
To examine the behavior of a function, equate the derivative to zero.
\The values are
and
.
The function is .
The domain of the function is .
There are four regions to examine the behavior of the function.
\First region .
Consider a test point in the region.
.
The derivative is negative, the function is decreasing over .
Second region .
Consider a test point in the region.
.
The derivative is positive, the function is increasing over .
Third region .
Consider a test point in the region.
The derivative is negative, the function is decreasing over .
Fourth region .
Consider a test point in the region.
The derivative is positive, the function is increasing over .
A monotonic function is increasing over and
.
A monotonic function is decreasing over and
.
Therefore the function is not strictly monotonic.
\The function is not strictly monotonic.