Also
lim
( )
x
c f x
→
 = lim
x
c x
c
→
=                  (Why )
Since lim
( )
( )
x
c f x
f c
→
=
, f is continuous at all positive real numbers Hence, f
is continuous at all points Example 8 Discuss the continuity of the function f given by f (x) = x3 + x2 – 1