Tuesday, February 28, 2012

12.1 Limits


If f(x) becomes arbitrarily close to a unique number L as x approaches c from either side, the limit of f(x) as x approaches c is L.

Note: As x gets closer to c, the closer y gets to L

Example:
  • One way to solve this is by putting 2 in for x.
  • Another way is to make a table

x

1.9

1.99

1.999

2

2.001

F(x)

4.7

4.97

4.997

5

5.003






The closer x gets to 2 (from both sides) the closer f(x) gets to 5

Describing the limit
Limits that Do Not Exist (DNR):

  1. when the left and right behaviors are different
the limit from the left would be -2, but the limit from the right would be 2.
The limit from the left side is described as
The - sign above the 2 shows it is from the left side
The limit from the right side is 2 (c) with a + sign

2. If a function increases without a bound, f(x) can be as large as you want
The asymptote of x=0 causes you to be able to choose a number as close to 0 and it keeps decreasing

3. When it Oscillates between two different numbers
the limit just switches between 1 and -1.













Continuity:
If a function is continuous at c then
  • A trick for knowing if a graph is continuous is if you can draw it out without lifting up your pencil.
  • Discontinuous graphs include: BREAKS, HOLES AND ASYMPTOTES



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