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Calculus: Early Transcendentals
(a) Show that the absolute value function $ F(x) = | x | $ is continuous everywhere.
(b) Prove that if $ f $ is a continuous function on an interval, then so is $ | f | $.
(c) Is the converse of the statement in part (b) also true? In other words, if $ | f | $ is continuous, does it follow that $ f $ is continuous? If so, prove it. If not, find a counterexample.