(iv) The graph of the function f is shown below

Of the following options, at what values of x is the function ƒ NOT differentiable?
(a) At x = 0 and x = 2
(b) At x= 1 and x = 3
(c) At x=-1 and x = 1
(d) At x=-1.5 and x = 1.5

Solution