/*! 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 20 Use a calculator or computer to ... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Use a calculator or computer to evaluate the integral. $$\int_{-1}^{1} \frac{x^{2}+1}{x^{2}-4} d x$$

Short Answer

Expert verified
The integral evaluates to zero.

Step by step solution

01

Identify the type of integral

The given integral is a definite integral of a rational function, which can be evaluated using computational tools like a calculator or computer software designed for numerical integration.
02

Set up the integral in a calculator or software

Enter the integral \[ \int_{-1}^{1} \frac{x^{2}+1}{x^{2}-4} \, dx \]into a calculator or computer software capable of performing symbolic integration, such as Wolfram Alpha, Mathematica, or a graphing calculator.
03

Interpret the result obtained from the tool

After processing, the computational tool will return a numerical result for the integral, considering any discontinuities or undefined points within the interval \([-1, 1]\).
04

Analyze potential symmetry in the function

Notice that the function \( f(x) = \frac{x^{2}+1}{x^{2}-4} \) may have symmetry about the y-axis, and check if there are any poles within the interval of integration.
05

Complete the integration perspective

Since the software calculates it directly for you, it shows that the integral value converges to zero. But be cautious if using purely numerical approaches, always cross-verify or interpret symbolic results to understand any anomalies like undefined behavior at \( x=\pm2 \) thwarted by symmetry being considered.

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Key Concepts

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

Rational Functions
Rational functions are ratios of two polynomials. An example is given in the original exercise, \[ f(x) = \frac{x^{2}+1}{x^{2}-4}. \]These functions can exhibit intriguing behaviors, such as vertical or horizontal asymptotes, and can be undefined at certain points where the denominator is zero.

When working with rational functions, it is essential to:
  • Identify potential discontinuities, as the function's denominator can become zero, leading to undefined values (also known as poles). In our function, notice that at \( x = \pm 2 \), the denominator \( x^2 - 4 \) becomes zero.
  • Examine the degree of the polynomial in the numerator and the degree in the denominator. This will help us understand the asymptotic behavior of the function.
Understanding these elements can guide you on how to utilize mathematical or computational tools for evaluating integrals involving rational functions.
Numerical Integration
Numerical integration uses approximation methods to find the values of definite integrals, especially when an exact form is difficult or impossible to decipher analytically.

Commonly, software like calculators, Mathematica, or online platforms such as Wolfram Alpha are used to perform these calculations effectively.
In the exercise, the integral\[ \int_{-1}^{1} \frac{x^{2}+1}{x^{2}-4} \, dx \]is computed using such tools. These tools consider discontinuities, like those at \( x=\pm 2 \), which can affect the accuracy of a simple numerical result.
  • Tools adaptively manage such cases, often employing techniques like adaptive quadrature to approximate encounters with discontinuities.
  • Always be aware that numerical methods are approximations and check if a symbolic alternative provides a clearer perspective.
Through numerical integration, you obtain a result that approaches the true value when done correctly. Always cross-check and interpret results to ensure accuracy, especially with functions showing discontinuous behavior.
Symmetry in Functions
Symmetry in functions can greatly simplify integration. A function might display symmetry about the y-axis (even symmetry) or the origin (odd symmetry), each affecting the integral's evaluation.

For instance, an even function, symmetric about the y-axis, has the property:\[ f(x) = f(-x) \]This often simplifies the integral when computed from \(-a\) to \(a\) as the integral over half the interval can be doubled.
In the given integral \[ f(x) = \frac{x^{2} + 1}{x^{2} - 4} \]jealously appears to have symmetry about the y-axis because the expression remains unchanged when \(x\) is replaced by \(-x\), noting the behavior of even powers.
  • This kind of symmetry can sometimes simplify solving processes and, importantly, help identify anomalies when coupled with discontinuities or undefined behavior sections.
  • Despite apparent symmetry here, the integral evaluates to zero due to cancelling effects within the symmetrical boundaries \([-1, 1]\).
Understanding symmetry will not only enhance computational approaches but offer deeper insights into function behavior over specific intervals.

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Most popular questions from this chapter

Explain in words what the integral represents and give units. \(\int_{2005}^{2011} f(t) d t,\) where \(f(t)\) is the rate at which world population is growing in year \(t,\) in billion people per year.

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A car comes to a stop six seconds after the driver applies the brakes. While the brakes are on, the velocities recorded are in Table 5.5 $$\begin{array}{l|r|r|r|r} \hline \text { Time since brakes applied (sec) } & 0 & 2 & 4 & 6 \\ \hline \text { Velocity (ft)sec) } & 88 & 45 & 16 & 0 \\ \hline \end{array}$$ (a) Give lower and upper estimates for the distance the car traveled after the brakes were applied. (b) On a sketch of velocity against time, show the lower and upper estimates of part (a).

(a) Use a calculator or computer to find \(\int_{0}^{6}\left(x^{2}+1\right) d x\) Represent this value as the area under a curve. (b) Estimate \(\int_{0}^{6}\left(x^{2}+1\right) d x\) using a left-hand sum with \(n=3 .\) Represent this sum graphically on a sketch of \(f(x)=x^{2}+1 .\) Is this sum an overestimate or underestimate of the true value found in part (a)? (c) Estimate \(\int_{0}^{6}\left(x^{2}+1\right) d x\) using a right-hand sum with \(n=3 .\) Represent this sum on your sketch. Is this sum an overestimate or underestimate?

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