DEFINITION Let f be a function defined on some open interval that con-
tains the number a, except possibly at a itself. Then we say that the limit of
f(x) as x approaches a is L, and we write
lim f(x) = L
x→a
if for every number &> 0 there is a corresponding number 8 >0 such that
| ƒ(x) − L| < ɛ
if 0 < x-a <8 then