Infact, such a point
is called point of inflexion ® Second Derivative Test Let f be a function defined on an interval I and
c ∈ I Let f  be twice differentiable at c Then
 (i) x = c is a point of local maxima if f ′(c) = 0 and f ″(c) < 0
The values f (c) is local maximum value of  f