How do you find vertical, horizontal and oblique asymptotes for (x^2-x+1)/(x-3)?

1 Answer
Dec 15, 2016

The vertical asymptote is x=3
No horizontal asymptote.
The oblique asymptote is y=x+2

Explanation:

As you cannot divide by 0, x!=3

Therefore,

The vertical asymptote is x=3

As the degree of the numerator is > than the degree of the denominator, we expect an oblique asymptote.

Let's do a long division

color(white)(aaaa)x^2-x+1color(white)(aaaa)x-3

color(white)(aaaa)x^2-3xcolor(white)(aaaaaaa)x+2

color(white)(aaaaa)0+2x+1

color(white)(aaaaaaa)+2x-6

color(white)(aaaaaaa)+0+7

Therefore,

(x^2-x+1)/(x-3)=x+2+7/(x-3)

The oblique asymptote is y=x+2

There is no horizontal asymptote. When x->+-oo,

f(x)->+-oo

graph{(y-(x^2-x+1)/(x-3))(y-x-2)=0 [-41.1, 41.1, -20.56, 20.56]}