What are the steps to finding an oblique asymptote for a rational function?

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In summary, the oblique asymptote of the given rational function f(x) is x + 4. This means that as x approaches infinity, the function will approach the line y = x + 4. It is necessary to use long division to find the oblique asymptote when the degree of the numerator is equal to or greater than the degree of the denominator. A point discontinuity occurs at the point (4,8) where the function has a discontinuity. This is equivalent to the line y = x + 4, with a discontinuity at x = 4 (where the denominator is zero). An oblique asymptote is also referred to as a slant asymptote because it is a line that is neither horizontal
  • #1
mathdad
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Find the oblique asymptote of f(x) = (x^2 - 16)/(x - 4). I need the steps not the solution.
 
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  • #2
f(x) simplifies to x + 4, which is the oblique asymptote of f(x).
 
  • #3
greg1313 said:
f(x) simplifies to x + 4, which is the oblique asymptote of f(x).

I get that the oblique asymptote is a line. Perhaps, I need an example that is a bit more involved.

When is it required for me to use long division to find the oblique asymptote?

Since the oblique asymptote is the line x + 4, what exactly does that mean?
 
  • #4
The given rational function does not have an oblique asymptote ... it has a point discontinuity at the point (4,8)
 
  • #5
1. What is a point discontinuity?

2. Where did (4,8) come from?
 
  • #6
skeeter said:
The given rational function does not have an oblique asymptote ... it has a point discontinuity at the point (4,8)

My mistake. It is equivalent to the line y = x + 4, with a discontinuity at x = 4 (where the denominator is zero).
 
  • #7
greg1313 said:
My mistake. It is equivalent to the line y = x + 4, with a discontinuity at x = 4 (where the denominator is zero).

You are saying that at x = 4, there is discontinuity. In other words, there is a hole in the graph of the function at the point (4, 8), right?

Why is an oblique asymptote called a slant asymptote?
 
  • #8
RTCNTC said:
You are saying that at x = 4, there is discontinuity. In other words, there is a hole in the graph of the function at the point (4, 8), right?

Yes

RTCNTC said:
Why is an oblique asymptote called a slant asymptote?

Because the oblique asymptote is a line that is neither horizontal (horizontal asymptote) nor vertical (vertical asymptote), but slanted.
 
  • #9
This weekend, I will post several rational functions and my solution to each problem.
 

FAQ: What are the steps to finding an oblique asymptote for a rational function?

What is an oblique asymptote?

An oblique asymptote is a type of asymptote that occurs when a function approaches a line at infinity, but does not intersect or touch the line. This line is typically slanted or tilted, and is often referred to as a "slant asymptote".

How do you find the equation of an oblique asymptote?

To find the equation of an oblique asymptote, you must first determine the degree of the numerator and denominator of the function. Then, you can use long division or synthetic division to divide the numerator by the denominator. The resulting quotient will be the equation of the oblique asymptote.

Can a function have more than one oblique asymptote?

Yes, it is possible for a function to have more than one oblique asymptote. This can occur when the function has a complex or multi-part structure, such as a rational function with multiple terms in the numerator and denominator.

How do you graph an oblique asymptote?

To graph an oblique asymptote, you must first plot the points of the function on a coordinate plane. Then, use the equation of the oblique asymptote to draw a dotted line that extends infinitely in both directions. Finally, plot additional points on the function to show how it approaches but does not touch the asymptote.

Can an oblique asymptote ever intersect with the function?

No, by definition, an oblique asymptote does not intersect with the function. If the function and the asymptote were to intersect, they would no longer be considered asymptotes. However, the function may approach the asymptote as closely as desired, making it appear as though they intersect.

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