2. Meaning of Limit:
Limits are the core tool that we build upon for calculus.
Many times, a function can be undefined at a point, but we
can think about what the function "approaches" as it gets
closer and closer to that point (this is the "limit").
Other times, the function may be defined at a point, but it
may approach a different limit.
There are many, many times where the function value is the
same as the limit at a point.
Either way, this is a powerful tool as we start thinking about
slope of a tangent line to a curve.
3. Meaning of x → a:
If a variable x takes increasing or decreasing values all
approximately to a but x does not equal a, we say that x
tends to a.
Symbolically write x → a.
4. Meaning of x → 0
When a variable x approaches 0 by taking decreasing
positive values or increasing negative values but x does
not become 0, then we say that x tends to 0 and write x →
0.
5. Meaning of x →∞
When a variable x takes larger and larger values such that
value of x is greater than a large positive number N, then
we say that x tends to infinity and write x →∞ .
6. Definition: Limit
Suppose f(x) is a function of real variable x.
If the function f(x) approaches closer and closer to a fixed
value ‘l’, when the variable ‘x’ approaches closer and
closer to a fixed value ‘a’, then we say that when x tends
to ‘a’, f(x) tends to ‘l’.
Symbolically, when x → a , f(x) → l.
lim x → a f(x) = l
9. Important formula for limits:
(1)
(2)
(3)
(4)
1
lim
n n
n
x a
x a
na
x a
0
1
lim log
x
e
x
a
a
x
1
lim 1
n
n
e
n
1
0
lim 1 m
m
m e