Vertical/Horizontal Asymptotes

  • Thread starter tachu101
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In summary, the vertical asymptotes of the function f(x)=(4x^2+25)/(x^2+9) do not exist, as the denominator can never be zero for real values of x. The horizontal asymptote is y=4.
  • #1
tachu101
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Homework Statement


Find the Vertical and horizontal asymptotes of this function

f(x)=(4x^2+25)/(x^2+9)


The Attempt at a Solution



I think that the horizontal asym. is y=4
But the Vertical if (x^2+9)=0 then x is an imaginary number. So is the asym. (3i) or does the asym not exist?
 
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  • #2
You are right on horizontal. For the second one, no, does not exist. Vertical asymptotes apply to real functions. For complex, the corresponding concept is called a 'pole'.
 
  • #3
tachu101 said:
But the Vertical if (x^2+9)=0 then x is an imaginary number.

For (real-valued) rational functions of polynomials, you will have a vertical asymptote where the denominator is zero, unless the numerator is also zero there. (If that happens, you have to look for cancelling terms or look at the limit of the ratio as x approaches the value where both "top" and "bottom" are zero.)

In the case of your function, the denominator can never be zero (for x real), so the rational function is always defined. So it will have no vertical asymptotes.
 

What is a vertical asymptote?

A vertical asymptote is a line on a graph that a function approaches but never touches as the input values approach a certain value. It is typically represented by a dashed line on a graph and indicates a point where the function becomes undefined.

How do I find the vertical asymptote of a function?

To find the vertical asymptote of a function, set the denominator of the function equal to 0 and solve for the input value. This input value will be the x-coordinate of the vertical asymptote.

What is a horizontal asymptote?

A horizontal asymptote is a line on a graph that a function approaches as the input values approach infinity or negative infinity. It represents the long-term behavior of the function and can be used to determine the end behavior of the graph.

How do I find the horizontal asymptote of a function?

To find the horizontal asymptote of a function, compare the degrees of the numerator and denominator of the function. If the degree of the numerator is less than the degree of the denominator, the horizontal asymptote is 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.

Can a function have multiple vertical or horizontal asymptotes?

Yes, a function can have multiple vertical and horizontal asymptotes. This occurs when there are multiple input values that make the function undefined or when the function has multiple long-term behaviors as the input values approach infinity or negative infinity.

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