Limit the expected / intended value of a function A limit can involve ∞ in two ways: You can expect a limit to be equal to ±∞ (vertical asymptote, limit DNE) You can expect a value of a function as x approaches ±∞ (horizontal asymptote)
As x approaches 3, the value of this function approaches ∞… the limit does not exist
RHL ≠ LHL; neither limit has a defined value From right From left
When you cannot “get rid of” division by zero in a limit, this represents a vertical asymptote The limit approaches ±∞ The limit does not exist
As x gets larger and larger (approaches ∞) what is the intended value of this function?
If no horizontal asymptote exists
To evaluate without graphing, you compare the largest degree of the denominator to the largest degree of the numerator
As x gets larger, denominator > numerator, smaller # / larger # gives smaller and smaller quotients… the overall result will tend towards zero
As x gets larger, numerator > denominator, larger # / smaller # gives larger and larger results… the overall results is that the value of the function continues to grow and there will be no asymptote
As x gets larger, the numerator and denominator grow in proportion to each other and the effect of lower-degree terms becomes less Value of the function as x approaches ±∞ equals the ratio of the coefficients of the largest degrees
There is no horizontal asymptote; the limit does not exist
Graphically there is a horizontal asymptote, can also use Sandwich / Squeeze Theorem
Rules apply for approaching +∞ or - ∞ Often there is little, if any work to show Graph and record answer in blank provided Circle relevant exponents and record answer Watch out for questions involving several fractions combine to a single fraction first