Table of contents
- 0. Review of Algebra4h 16m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations43m
- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
- 7. Systems of Equations & Matrices4h 6m
- 8. Conic Sections2h 23m
- 9. Sequences, Series, & Induction1h 19m
- 10. Combinatorics & Probability1h 45m
5. Rational Functions
Graphing Rational Functions
Problem 58a
Textbook Question
In Exercises 57–64, find the vertical asymptotes, if any, the horizontal asymptote, if one exists, and the slant asymptote, if there is one, of the graph of each rational function. Then graph the rational function. g(x) = (2x - 4)/(x + 3)
![](/channels/images/assetPage/verifiedSolution.png)
1
Identify the vertical asymptotes by setting the denominator equal to zero and solving for \(x\). For the function \(g(x) = \frac{2x - 4}{x + 3}\), set \(x + 3 = 0\).
Solve the equation \(x + 3 = 0\) to find the vertical asymptote. This will give you the value of \(x\) where the function is undefined.
Determine the horizontal asymptote by comparing the degrees of the numerator and the denominator. Since both the numerator \(2x - 4\) and the denominator \(x + 3\) are of degree 1, the horizontal asymptote is \(y = \frac{2}{1}\).
Check for a slant asymptote. Since the degrees of the numerator and denominator are equal, there is no slant asymptote for this function.
Graph the function using the asymptotes as guides. Plot the vertical asymptote as a dashed line at the value of \(x\) found in step 2, and the horizontal asymptote as a dashed line at \(y = 2\). Then sketch the curve of the function, approaching these asymptotes.
Recommended similar problem, with video answer:
![](/channels/images/assetPage/verifiedSolution.png)
This video solution was recommended by our tutors as helpful for the problem above
Video duration:
7mPlay a video:
Was this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Vertical Asymptotes
Vertical asymptotes occur in rational functions where the denominator equals zero, leading to undefined values. To find vertical asymptotes, set the denominator of the function to zero and solve for x. For the function g(x) = (2x - 4)/(x + 3), the vertical asymptote is at x = -3, where the denominator becomes zero.
Recommended video:
Determining Vertical Asymptotes
Horizontal Asymptotes
Horizontal asymptotes describe the behavior of a function as x approaches infinity or negative infinity. For rational functions, the horizontal asymptote can be determined by comparing the degrees of the numerator and denominator. In g(x), since the degrees are equal, the horizontal asymptote is found by taking the ratio of the leading coefficients, which is y = 2/1 = 2.
Recommended video:
Determining Horizontal Asymptotes
Slant Asymptotes
Slant (or oblique) asymptotes occur when the degree of the numerator is exactly one greater than the degree of the denominator. To find a slant asymptote, perform polynomial long division. In the case of g(x), since the degree of the numerator (1) is not greater than that of the denominator (1), there is no slant asymptote.
Recommended video:
Introduction to Asymptotes
Watch next
Master Graphing Rational Functions Using Transformations with a bite sized video explanation from Callie
Start learningRelated Videos
Related Practice