/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 14 Let \(f(x)=\frac{-x-3}{x^{2}-5 x... [FREE SOLUTION] | 91Ó°ÊÓ

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Let \(f(x)=\frac{-x-3}{x^{2}-5 x-14}, g(x)=\frac{x-x^{3}}{x-3}, h(x)=\frac{x^{3}-1}{x^{2}+4},\) and \(r(x)=\frac{x^{2}+x-6}{x^{2}-16} .\) How can you can tell from its equation which of these functions has, a. a horizontal asymptote? b. an oblique asymptote? c. no vertical asymptote? Explain. Determine the equations of all asymptote(s) for each function. Describe the behaviour of each function close to its asymptotes.

Short Answer

Expert verified
f(x) and r(x) have horizontal asymptotes; h(x) has an oblique asymptote; g(x) has no vertical asymptote.

Step by step solution

01

Identify horizontal asymptotes

For horizontal asymptotes, we compare the degrees of the numerator and the denominator.- **Function f(x):** The degree of the numerator is 1 and the degree of the denominator is 2. Since the numerator's degree is less, there's a horizontal asymptote at \( y = 0 \).- **Function g(x):** The degree of the numerator is 3 and the degree of the denominator is 1. More details in Step 2.- **Function h(x):** The degree of the numerator is 3 and the degree of the denominator is 2. More details in Step 2.- **Function r(x):** Both numerator and denominator have degree 2. The leading coefficients are both 1, so the horizontal asymptote is \( y = 1 \).Thus, **f(x)** and **r(x)** have horizontal asymptotes.
02

Determine oblique (slant) asymptotes

Oblique asymptotes occur when the degree of the numerator is exactly one more than that of the denominator.- **Function g(x):** The numerator degree (3) is greater than the denominator degree (1) by more than one, leading to no asymptotes in this category.- **Function h(x):** The numerator degree (3) is one more than the denominator degree (2). Use polynomial long division:Perform \( x^3 - 1 \div (x^2 + 4) \). The result shows an oblique asymptote: \( y = x \).Thus, **h(x)** has an oblique asymptote.
03

Identify vertical asymptotes

Vertical asymptotes occur where the denominator is zero and the numerator is non-zero.- **Function f(x):** Set \( x^2 - 5x - 14 = 0 \) which factors to \( (x-7)(x+2) = 0 \), giving \( x = 7 \) and \( x = -2 \).- **Function g(x):** The denominator is zero at \( x = 3 \). However, the numerator is also zero at this point, so there's no vertical asymptote due to cancellation.- **Function h(x):** No asymptotes occur since it doesn't have repeated factors in the denominator causing direct zero.- **Function r(x):** Set \( x^2 - 16 = 0 \), which gives \( x = 4 \), \( x = -4 \).Thus, **f(x)** and **r(x)** have vertical asymptotes, **g(x)** has none.
04

Describe behavior near asymptotes

Determine the function's behavior as \( x \to \) asymptotes:- **f(x):** As \( x \to 7^- \) or \( x \to 7^+ \), \( f(x) \to \pm \infty \). As \( x \to -2^- \) or \( x \to -2^+ \), \( f(x) \to \pm \infty \). As \( x \to \pm \infty \), \( f(x) \to 0 \).- **g(x):** As \( x \to 3 \), no vertical asymptote behavior since \( g(x) \) simplifies at \( x = 3 \). As \( x \to \pm \infty \), it approaches \( x^2 \).- **h(x):** Close to \( x = y = x \), approach from above/below shows \( h(x) \to x \).- **r(x):** As \( x \to 4^-/4^+ \) or \( x \to -4^-/-4^+ \), behavior is \( r(x) \to \pm \infty \). As \( x \to \pm \infty \), \( r(x) \to 1 \).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Horizontal Asymptote
A horizontal asymptote gives us a sense of where a function will level out as it heads towards positive or negative infinity. Here's how you find one:
  • Compare the degrees (the highest power of the variable) 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 the x-axis, or in mathematical terms, \( y = 0 \).
  • If the degrees are the same, the horizontal asymptote is given by the ratio of their leading coefficients. So if each has a leading coefficient of 1, \( y = 1 \).
Let's break it down with examples:- **For** \( f(x)=\frac{-x-3}{x^2-5x-14} \), the degree is higher in the denominator, resulting in a horizontal asymptote at \( y = 0 \).- **For** \( r(x)=\frac{x^2+x-6}{x^2-16} \), both the numerator and denominator have the same degree, which places the horizontal asymptote at \( y = 1 \).These asymptotes help us visualize how the graph of the function behaves as it stretches towards infinity.
Oblique Asymptote
The oblique or slant asymptote might seem tricky at first, but it's all about the degree of the functions:
  • They appear when the degree of the numerator is exactly one higher than the degree of the denominator.
  • To find an oblique asymptote, perform polynomial long division on the functions involved.
For our problem, let's see how it works:- **For** \( h(x)=\frac{x^3-1}{x^2+4} \), we find the numerator's degree is one more than the denominator's degree. By dividing \( x^3 - 1 \) by \( x^2 + 4 \), we get an oblique asymptote at \( y = x \).The graph not only tells us about a function's direction as it goes to infinity, but for slanting lines, it offers a linear boundary the function will approach but never reach.
Vertical Asymptote
Vertical asymptotes are found by identifying points where the function's denominator equals zero while the numerator does not:
  • These lines occur when a division by zero happens that doesn't get "cancelled out" by the numerator.
  • They often represent values of \( x \) that produce outputs approaching infinity as we approach these points.
For our functions, let's examine:- **For** \( f(x)=\frac{-x-3}{x^2-5x-14} \), solving \( x^2 - 5x - 14 = 0 \) gives roots at \( x = -2 \) and \( x = 7 \), creating vertical asymptotes there.- **For** \( r(x)=\frac{x^2+x-6}{x^2-16} \), \( x^2 - 16 = 0 \) produces vertical asymptotes at \( x = -4 \) and \( x = 4 \).However, for \( g(x)=\frac{x-x^3}{x-3} \), the numerator and denominator reach zero simultaneously at \( x = 3 \), eliminating vertical asymptotes due to simplification. Understanding these points allows for accurate depiction of function behavior rather than assumptions of undefined values.

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Most popular questions from this chapter

Find constants \(a, b,\) and \(c\) such that the function \(f(x)=a x^{3}+b x^{2}+c\) will have a local extremum at (2,11) and a point of inflection at \((1,5) .\) Sketch the graph of \(y=f(x)\)

Find constants \(a\) and \(b\) such that the graph of the function defined by \(f(x)=\frac{a x+5}{3-b x}\) will have a vertical asymptote at \(x=5\) and a horizontal asymptote at \(y=-3\).

If a polynomial function of degree three has a local minimum, explain how the function's values behave as \(x \rightarrow+\infty\) and as \(x \rightarrow-\infty\). Consider all cases.

Sketch the graph of a function with the following properties: \(\cdot\) \(f^{\prime}(x) > 0\) when \(x < 2\) and when \(2 < x < 5\) \(\cdot\) \(f^{\prime}(x) < 0\) when \(x > 5\) \(\cdot\) \(f^{\prime}(2)=0\) and \(f^{\prime}(5)=0\) \(\cdot\) \(f^{\prime \prime}(x) < 0\) when \(x<2\) and when \(4 < x < 7\) \(\cdot\) \(f^{\prime \prime}(x) > 0\) when \(2 < x < 4\) and when \(x > 7\) \(\cdot\) \(f(0)=-4\)

Given the following results of the analysis of a function, sketch a possible graph for the function: a. \(f(0)=0,\) the horizontal asymptote is \(y=2,\) the vertical asymptote is \(x=3,\) and \(f^{\prime}(x)<0\) and \(f^{\prime \prime}(x)<0\) for \(x<3 ; f^{\prime}(x)<0\) and \(f^{\prime \prime}(x)>0\) for \(x>3\) b. \(f(0)=6, f(-2)=0\) the horizontal asymptote is \(y=7,\) the vertical asymptote is \(x=-4,\) and \(f^{\prime}(x)>0\) and \(f^{\prime \prime}(x)>0\) for \(x<-4\) \(f^{\prime}(x)>0\) and \(f^{\prime \prime}(x)<0\) for \(x>-4\)

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