Precalculus Examples

Find the Asymptotes (3x^2-5x-12)/(x^2-9)
Step 1
Find where the expression is undefined.
Step 2
Since as from the left and as from the right, then is a vertical asymptote.
Step 3
Consider the rational function where is the degree of the numerator and is the degree of the denominator.
1. If , then the x-axis, , is the horizontal asymptote.
2. If , then the horizontal asymptote is the line .
3. If , then there is no horizontal asymptote (there is an oblique asymptote).
Step 4
Find and .
Step 5
Since , the horizontal asymptote is the line where and .
Step 6
There is no oblique asymptote because the degree of the numerator is less than or equal to the degree of the denominator.
No Oblique Asymptotes
Step 7
This is the set of all asymptotes.
Vertical Asymptotes:
Horizontal Asymptotes:
No Oblique Asymptotes
Step 8