Find the local maxima and local minima, if any, of the following functions. Find also the local maximum and the local minimum values, as the case may be:
g(x) = x3 – 3x
g(x) = x3 – 3x
⇒ g’(x) = 3x2 - 3
Now, g’(x) = 0
⇒ 3x2 - 3 = 0
⇒ 3x2 = 3
⇒ x = � 1
g’’(x) = 6x
Now, g’(1) = 6>0
and g’(-1) = -6 < 0
Then, by second derivative test,
⇒ x = 1 is point of local maxima and local minima of g at x = 1 is
g(1) = 13 – 3 = 1-3 =-2
And,
x = -1 is point of local maxima and local maximum value of g at x = -1 is
g(-1) = (-1)3 – 3(-1) = -1+3 = 2