In Exercises the function is differentiable on the indicated interval. The table shows '(x) for selected values of x. (a) Sketch the graph of

In Exercises the function ƒ is
differentiable on the indicated interval. The table shows ƒ'(x)
for selected values of x. 

(a) Sketch the graph of ƒ

(b) Approx-mate the critical numbers

(c) Identify the relative extrema

ƒ is differentiable on [−1, 1].

f'(x) -1 - 10 0.25 -0.75 -0.50 -0.25 -3.2 0.50 f'(x) 3.6 -0.2 -0.5 0.75 -6.7 0.8 1 - 20.1 0 5.6