/*! 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 35 Graph the solution of \(y^{\prim... [FREE SOLUTION] | 91Ó°ÊÓ

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Graph the solution of \(y^{\prime}=y^{2}-1, y(0)=3,\) given in exercise \(34 .\) Find an equation of the vertical asymptote. Explain why Euler's method would be "unaware" of the existence of this asymptote and would therefore provide very unreliable approximations.

Short Answer

Expert verified
The exact solution to the differential equation is \( y = \pm\sqrt{e^{x+\ln|8|}+1}\), the vertical asymptotes are at \( y = 1 \) and \( y = -1 \). Euler's method fails to predict asymptotic behavior because it assumes that the function's slope remains roughly constant for small intervals – however, this is not the case near asymptotes.

Step by step solution

01

Solving the Differential Equation

This is a separable differential equation. First, separate variables so that all \(y\) terms are on one side of the equation and all \(x\) terms are on the other. The adjusted equation is \(\frac{dy}{y^{2}-1} = dx\). Now, integrate both sides.\nThus solve the differential equation by anti-differentiating both sides of the equation. This gives us: \( \ln |y^{2}-1| = x + C\) where \(C\) is the constant of integration.\nThe initial condition \(y(0) = 3\) can be substituted into the general solution to solve for \(C\). Therefore, \(C = \ln|3^{2} - 1|\). Thus the exact solution to the differential equation is \( y = \pm\sqrt{e^{x+\ln|8|}+1}\).
02

Graphing the Solution and Locating the Asymptote

Design y as a function of x: \(y = \pm\sqrt{e^{x+ln|8|} + 1} \), the curves intersect at \(y = \pm 1\) as time progresses when the exponent becomes large, the function will tend toward \(y = \pm 1\). So, the vertical asymptotes of the graph of the solution to the differential are \(y = 1\) and \(y = -1\).
03

Understanding the Contentual Limitations of Euler's method

Euler’s method is a numerical method that is used to approximate the solution to a differential equation. However, it cannot detect the presence of an asymptote. This is because the method is based on using an approximation to the slope (the derivative) to predict future function values, and the presence of an asymptote implies a sharp change in function values which can not be predicted by the constant slope assumption. The slope of the tangent line approaches infinity as it reaches the asymptote, while Euler's method operates under the assumption that the slope of the function remains roughly constant for small intervals, which is not the case near asymptotes. Therefore, Euler's method would provide very unreliable approximations for functions with asymptotic behavior.

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Key Concepts

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

Euler's Method Limitations
Euler's Method is a fundamental tool for numerically approximating solutions to differential equations, especially when an analytical solution is difficult or impossible to obtain. Despite its straightforward approach, Euler's Method has its limitations and one of the most significant is its inability to detect or handle vertical asymptotes accurately. Vertical asymptotes occur in functions where the output tends toward infinity as the input approaches a certain value. Because Euler's Method relies on the assumption of a nearly constant slope over small intervals, it cannot anticipate the infinite slope presented by an asymptote. Consequently, Euler's Method would predict a finite value instead of heading towards infinity, leading to significant error. As a result, students must keep in mind the limitations of this method when dealing with differential equations that may involve asymptotic behavior.
Solving Separable Differential Equations
Separable differential equations are a class of differential equations that can be rearranged so that all the terms involving one variable are on one side of the equation and those involving the other variable are on the opposite side. The key steps involve separation of variables and integration.

For instance, when solving the equation \(y^{\text{'}}=y^{2}-1\), one would first write it as \(\frac{dy}{y^{2}-1} = dx\), separating the variables. Following this, each side of the equation is integrated independently. The integration results in an equation involving an arbitrary constant, which can be determined using initial conditions, if provided. Students should pay special attention to ensure the separation is correctly done, and the right antiderivatives are chosen during the integration process.
Graphing Differential Equation Solutions
Graphing solutions of differential equations allows for a visual interpretation of the behavior of dynamic systems. When graphing the solutions, students should consider equilibrium points where the derivative is zero—these often correspond to horizontal asymptotes or constant solutions.

Equally important is the identification of potential vertical asymptotes, which signify points where the function may experience an abrupt change in value (usually infinity or negative infinity). To graph a solution accurately, one needs to understand the behavior of the function at different values of the independent variable, especially near any asymptotes or discontinuities.
Identifying Vertical Asymptotes in Functions
Vertical asymptotes are found in functions where the output grows without bound as the input approaches a specific value from either side. To identify vertical asymptotes in functions derived from differential equations, one must look for points where the function becomes undefined, or the limit of the function is infinity as x approaches a certain value.

For example, in the solution \(y = \pm\sqrt{e^{x+\ln|8|} + 1}\), the vertical asymptotes are at points where the radicand equals zero, which in this case corresponds to \(-1\) and \(-\infty\). However, it's crucial to note that not all discontinuities in a function's domain are vertical asymptotes; some may be holes or removable discontinuities. Students should learn to differentiate between these for a clear and correct understanding of the function's behavior.

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Most popular questions from this chapter

Suppose the income tax structure is as follows: the first \(\$ 30,000\) is taxed at \(15 \%,\) the remainder is taxed at \(28 \% .\) Compute the \(\operatorname{tax} T_{1}\) on an income of \(\$ 40,000 .\) Now, suppose that inflation is \(5 \%\) and you receive a cost of living \((5 \%)\) raise to \(\$ 42,000\) Compute the \(\operatorname{tax} T_{2}\) on this income. To compare the taxes, you should adjust the \(\operatorname{tax} T_{1}\) for inflation (add \(5 \%\) ).

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