Solution We may rewrite f as
f (x) =
, if
0
, if
0
x
x
x
x
−
<

≥

By Example 3, we know that f is continuous at x = 0 Let c be a real number such that c < 0 Then f(c) = – c Also
lim
( )
x
c f x
→
 = lim (
)
–
x
c
x
c
→
−
=
          (Why