Examples
y=x+1x2-1y=x+1x2−1
Step 1
Find where the expression x+1x2-1x+1x2−1 is undefined.
x=-1,x=1x=−1,x=1
Step 2
Since x+1x2-1x+1x2−1→→-∞−∞ as xx→→11 from the left and x+1x2-1x+1x2−1→→∞∞ as xx→→11 from the right, then x=1x=1 is a vertical asymptote.
x=1x=1
Step 3
Consider the rational function R(x)=axnbxmR(x)=axnbxm where nn is the degree of the numerator and mm is the degree of the denominator.
1. If n<mn<m, then the x-axis, y=0y=0, is the horizontal asymptote.
2. If n=mn=m, then the horizontal asymptote is the line y=aby=ab.
3. If n>mn>m, then there is no horizontal asymptote (there is an oblique asymptote).
Step 4
Find nn and mm.
n=1n=1
m=2m=2
Step 5
Since n<mn<m, the x-axis, y=0y=0, is the horizontal asymptote.
y=0y=0
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: x=1x=1
Horizontal Asymptotes: y=0y=0
No Oblique Asymptotes
Step 8