Q. The function be given by

Assertion (A) is not a point of local maxima.
Reason (R) is not a point of local minima.

 979  164 Application of Derivatives Report Error

Solution:

We have,

or
Now gives . Also, . Therefore, the second derivative test fails in this case. So, we shall go back to the first derivative test.
Using first derivatives test, we get is neither a point of local maxima nor a point of local minima and so it is a point of inflexion.