Find asymptotes for rational functions

In summary, the conversation discusses finding asymptotes for the function f(x) = (x^2 - 1) / (x - 1) and the conditions for determining them. The attempt at a solution suggests that the asymptote is x+1, but it is revealed that there is actually no asymptote for this function. The conversation also briefly touches on the graph of the function, which would be a straight line with a slope of 1.
  • #1
ssampak
5
0

Homework Statement



Find asymptotes for f(x) = (x^2 -1) / (x - 1). (if exist)

Homework Equations



g(x) is a (horizontal or oblique) asymptote if lim |f(x) - g(x)| = 0
(here, lim is to be limit as x goes to infinity. don't know how to type it)

or

if q(x)/p(x) = g(x) + r(x)/p(x) where dimension of r(x) is smaller than that of p(x)

The Attempt at a Solution



f(x) = (x^2 - 1) / (x-1) = x+1 (where x ≠ 1)

then lim |f(x) - (x+1)| = 0 so asymptote is x+1.

But the answer is 'no asymptote'. What am I missing?
 
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  • #2
If f(x) = (x^2 - 1) / (x-1) = x+1, the doesn't that just mean that f(x)=x+1 ? and that is what kind of graph?
 

What is an asymptote?

An asymptote is a line that a graph approaches but never touches. It can be either horizontal, vertical, or slanted.

How do you find asymptotes for rational functions?

To find asymptotes for rational functions, you first need to simplify the function by factoring out common factors and canceling out common terms. Then, you can identify any vertical asymptotes by setting the denominator equal to zero and solving for the variable. Horizontal asymptotes can be found by looking at the degrees of the numerator and denominator. If the degree of the numerator is less than the degree of the denominator, there is a horizontal asymptote at y = 0. If the degrees are equal, the horizontal asymptote is the ratio of the leading coefficients. If the degree of the numerator is greater than the degree of the denominator, there is no horizontal asymptote.

What is the difference between a removable and non-removable asymptote?

A removable asymptote is a point where the graph crosses the asymptote and can be removed by simplifying the function. A non-removable asymptote is a point where the graph approaches the asymptote but does not cross it.

Can a rational function have more than one asymptote?

Yes, a rational function can have multiple asymptotes. It can have both horizontal and vertical asymptotes, and it can also have multiple vertical asymptotes if there are multiple values of x that make the denominator equal to zero.

Why are asymptotes important in graphing rational functions?

Asymptotes help us understand the behavior of a graph as the input value approaches certain values. They also help us identify any discontinuities in the function. Additionally, asymptotes can help us determine the end behavior of a function and make predictions about its graph.

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