How do you graph f(x)=x^2/(x-1) using holes, vertical and horizontal asymptotes, x and y intercepts?

1 Answer
Feb 23, 2018

See explanation...

Explanation:

Alright, So for this question we are looking for six items - holes, vertical asymptotes, horizontal asymptotes, x intercepts, and y intercepts - in the equation f(x)=x^2/(x-1) First lets graph it

graph{x^2/(x-1 [-10, 10, -5, 5]}

Right off the bat you can see some strange things happening to this graph. Lets really break it down.

To begin, lets find the x and y intercept. you can find the x intercept by setting y=0 and vise versa x=0 to find the y intercept.

For the x intercept:
0=x^2/(x-1)

0=x

Therefore, x=0 when y=0. So without even knowing that information, we have just found BOTH the x and y intercept.

Next, lets work on the asymptotes. To find the vertical asymptotes, set the denominator equal to 0, then solve.

0=x-1

x=1

So we just found that there is a vertical asymptote at x=1. You can visually check this by looking at the above graph. Next, lets find the horizontal asymptote.

There are three general rules when talking about a horizontal asymptote.

1) If both polynomials are the same degree,divide the coefficients of the highest degree term.

2) If the polynomial in the numerator is a lower degree than the denominator, then y=0 is the asymptote.

3) If the polynomial in the numerator is a higher degree than the denominator, then there is no horizontal asymptote. It is a slant asymptote.

Knowing these three rules, we can determine that there is no horizontal asymptote, since the denominator is a lower degree than the numerator.

Finally, lets find any holes that might be in this graph. Now, just from past knowledge, we should know that no holes will appear in a graph with a slant asymptote. Because of this, lets go ahead and find the slant.

We need to do long division here using both polynomials:

=x^2/(x-1)

=x-1

I'm sorry that there isn't a great way to show you the long divition there, but if you have anymore questions about that, click here.

So there you go, I really hope this helped, and I apologize for the length!
~Chandler Dowd