End Behavior

Definition

End behavior refers to the behavior of a function as the input variable approaches positive or negative infinity. It describes the overall trend and characteristics of a function's values as the independent variable becomes increasingly large or small in magnitude.

5 Must Know Facts For Your Next Test

1. The end behavior of a function can be used to determine whether the function is increasing, decreasing, or oscillating as the input variable approaches positive or negative infinity.
2. Polynomial functions exhibit predictable end behavior, with the degree and leading coefficient determining whether the function approaches positive or negative infinity.
3. Rational functions may have vertical asymptotes, which indicate where the function is undefined, and horizontal asymptotes, which describe the function's end behavior.
4. Exponential functions approach positive or negative infinity depending on the sign of the exponent, while logarithmic functions approach positive or negative infinity as the input variable approaches positive or negative infinity, respectively.
5. Understanding end behavior is crucial for sketching the graph of a function and predicting its overall shape and characteristics.

Review Questions

• Explain how the end behavior of a polynomial function is determined by its degree and leading coefficient.
  • The end behavior of a polynomial function is determined by its degree and the sign of its leading coefficient. If the degree is even, the function will approach positive infinity as the input variable approaches positive infinity and negative infinity as the input variable approaches negative infinity, regardless of the sign of the leading coefficient. If the degree is odd, the function's end behavior will depend on the sign of the leading coefficient - a positive leading coefficient will result in the function approaching positive infinity as the input variable approaches positive infinity and negative infinity as the input variable approaches negative infinity, while a negative leading coefficient will have the opposite effect.
• Describe the relationship between end behavior and asymptotes for rational functions.
  • Rational functions can have two types of asymptotes: vertical asymptotes and horizontal asymptotes. Vertical asymptotes indicate where the function is undefined and correspond to the zeros of the denominator. The end behavior of a rational function is determined by the relative degrees of the numerator and denominator polynomials. If the degree of the numerator is less than the degree of the denominator, the function will have a horizontal asymptote at $y = 0$ as the input variable approaches positive or negative infinity. If the degree of the numerator is greater than the degree of the denominator, the function will approach positive or negative infinity as the input variable approaches positive or negative infinity, depending on the signs of the leading coefficients.
• Analyze how the end behavior of exponential and logarithmic functions differs and how this relates to their inverse relationship.
  • Exponential functions and logarithmic functions exhibit opposite end behaviors. Exponential functions with a positive base approach positive infinity as the input variable approaches positive infinity, and negative infinity as the input variable approaches negative infinity. Logarithmic functions, on the other hand, approach positive infinity as the input variable approaches positive infinity, and negative infinity as the input variable approaches positive infinity. This inverse relationship between exponential and logarithmic functions is a fundamental characteristic that allows them to be used as inverse operations, with the end behavior of one function mirroring the end behavior of the other.

Related terms

Asymptotes: Asymptotes are lines that a function's graph approaches but never touches as the input variable approaches positive or negative infinity.

Limits at Infinity: Limits at infinity describe the behavior of a function as the input variable approaches positive or negative infinity, and are used to determine the end behavior of the function.

Function Classification: The end behavior of a function is a key characteristic used to classify functions into basic categories such as polynomial, rational, exponential, and logarithmic functions.