(b) For what values of x is f differentiable? O x20 Ox :0 Ox>0 O all real x (c) Find a formula for f' where it is defined. F'( X) =(a) Sketch the graph of the function f(x) = x|x|. 4 X 2 4 -4 -2 2 4 -4 -2 -21 -4 -4 O O 4 X X -4 2 4 -4 -2 2 4 -2 -2 -2 -4 -4