Table of contents
- 0. Fundamental Concepts of Algebra3h 29m
- 1. Equations and Inequalities3h 27m
- 2. Graphs1h 43m
- 3. Functions & Graphs2h 17m
- 4. Polynomial Functions1h 54m
- 5. Rational Functions1h 23m
- 6. Exponential and Logarithmic Functions2h 28m
- 7. Measuring Angles40m
- 8. Trigonometric Functions on Right Triangles2h 5m
- 9. Unit Circle1h 19m
- 10. Graphing Trigonometric Functions1h 19m
- 11. Inverse Trigonometric Functions and Basic Trig Equations1h 41m
- 12. Trigonometric Identities 2h 34m
- 13. Non-Right Triangles1h 38m
- 14. Vectors2h 25m
- 15. Polar Equations2h 5m
- 16. Parametric Equations1h 6m
- 17. Graphing Complex Numbers1h 7m
- 18. Systems of Equations and Matrices3h 6m
- 19. Conic Sections2h 36m
- 20. Sequences, Series & Induction1h 15m
- 21. Combinatorics and Probability1h 45m
- 22. Limits & Continuity1h 49m
- 23. Intro to Derivatives & Area Under the Curve2h 9m
5. Rational Functions
Asymptotes
Struggling with Precalculus?
Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
Find the horizontal asymptote of each function.
f(x)=(2x+3)2−5x
A
Horizontal Asymptote at y=0
B
Horizontal Asymptote at y=−45
C
Horizontal Asymptote at y=−25

1
Identify the degrees of the polynomial in the numerator and the denominator. The numerator is -5x, which is a polynomial of degree 1. The denominator is (2x+3)^2, which is a polynomial of degree 2.
Compare the degrees of the numerator and the denominator. Since the degree of the numerator (1) is less than the degree of the denominator (2), the horizontal asymptote is y = 0.
If the degree of the numerator had been equal to the degree of the denominator, the horizontal asymptote would be the ratio of the leading coefficients.
If the degree of the numerator had been greater than the degree of the denominator, there would be no horizontal asymptote, but rather an oblique asymptote.
Conclude that for the given function f(x) = -5x / (2x+3)^2, the horizontal asymptote is y = 0.
Watch next
Master Introduction to Asymptotes with a bite sized video explanation from Patrick
Start learning