Proposition 6.1.7: Properties for limits of Functions
If
f(x)
exists, the limit is unique.

[ f(x) + g(x) ] =
f(x) +
g(x),
provided that
f(x)
and
g(x)
exist.
[ f(x) g(x) ] =
f(x)
g(x),
provided that
f(x)
and
g(x)
exist.
[ f(x) / g(x) ] =
f(x) /
g(x),
provided that
f(x)
and
g(x)
exist and
g(x) # 0.