/*! 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 51 Using EES (or other) software, s... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Using EES (or other) software, solve these systems of algebraic equations. (a) $$ \begin{array}{r} 3 x_{1}-x_{2}+3 x_{3}=0 \\ -x_{1}+2 x_{2}+x_{3}=3 \\ 2 x_{1}-x_{2}-x_{3}=2 \end{array} $$ (b) $$ \begin{aligned} 4 x_{1}-2 x_{2}^{2}+0.5 x_{3} &=-2 \\ x_{1}^{3}-x_{2}+x_{3} &=11.964 \\ x_{1}+x_{2}+x_{3} &=3 \end{aligned} $$

Short Answer

Expert verified
Question: Solve the following systems of algebraic equations using the provided steps: System (a): $$ 3x_1 - x_2 + 3x_3 = 0 \\ -x_1 + 2x_2 + x_3 = 3 \\ 2x_1 - x_2 - x_3 = 2 $$ System (b): $$ 4x_1 - 2x_2^2 + 0.5x_3 + 2 = 0\\ x_1^3 - x_2 + x_3 - 11.964 = 0\\ x_1 + x_2 + x_3 - 3 = 0 $$ Answer: For system (a), following the steps for solving a linear system of equations, we find the solution to be: $$ x_1 = 1\\ x_2 = 1\\ x_3 = 2 $$ For system (b), we set up the problem to be solved using an iterative method such as the Newton-Raphson method with the given Jacobian matrix and vector function. To find the solution, we must use a software tool, such as EES or another preferred tool capable of solving systems of nonlinear algebraic equations. A good initial guess must be provided, and the solution will depend on the chosen method's convergence properties.

Step by step solution

01

Determine the method to solve the linear system

In this case, we will use the matrix method, specifically the Gaussian Elimination method, to solve the given system of linear equations.
02

Set up the augmented matrix for the linear system

Rewrite the given system as an augmented matrix: $$ \left[\begin{array}{ccc|c} 3&-1&3&0\\ -1&2&1&3\\ 2&-1&-1&2 \end{array}\right] $$
03

Perform Gaussian Elimination

Eliminate the first element in the second and third rows by adding suitable multiples of the first row to the second and third rows, and then normalize the first row: $$ \left[\begin{array}{ccc|c} 1&-\frac{1}{3}&1&0\\ 0&\frac{5}{3}&4&3\\ 0&0&3&6 \end{array}\right] $$
04

Perform Back Substitution

Now that we have an upper triangular matrix, we can perform back substitution to obtain the values of the variables: $$ x_3 = \frac{6}{3} = 2\\ x_2 = \frac{3-(4)(2)}{\frac{5}{3}} = 1\\ x_1 = \frac{-(\frac{1}{3})(1) + 1(2)}{1} = 1 $$ For system (b):
05

Determine the method to solve the nonlinear system

In this case, we will use an iterative method, specifically, the Newton-Raphson method, to solve the given system of nonlinear equations.
06

Write down the system of nonlinear equations as a vector function

Rewrite the system of nonlinear equations as a vector function F(x) = [F_1(x), F_2(x), F_3(x)]: $$ F(x) = \begin{bmatrix} 4x_1 - 2x_2^2 + 0.5x_3 + 2 \\ x_1^3 - x_2 + x_3 - 11.964 \\ x_1 + x_2 + x_3 -3 \end{bmatrix} $$
07

Compute the Jacobian matrix for the vector function

Compute the partial derivatives of each function with respect to each variable to obtain the Jacobian matrix J(x): $$ J(x) = \begin{bmatrix} 4 & -4x_2 & 0.5 \\ 3x_1^2 & -1 & 1 \\ 1 & 1 & 1 \end{bmatrix} $$
08

Follow the iterative steps of the Newton-Raphson method

Iteratively solve the system using the Newton-Raphson method until a desired level of accuracy is reached. This involves updating the guess for the solution with each iteration according to the formula: $$ x_{k+1} = x_k - J(x_k)^{-1}F(x_k) $$ where x is the vector of unknowns, J(x) is the Jacobian matrix, and F(x) is the vector function. Note that this step is not easily done by hand and requires the use of a software tool, such as EES or another preferred tool capable of solving systems of nonlinear algebraic equations. The Newton-Raphson method may require a good initial guess to converge to the correct solution. Other numerical methods such as Broyden's method or fixed-point iteration methods may be more appropriate depending on the specific problem and initial guess.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

Key Concepts

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

Gaussian Elimination
Gaussian Elimination is a systematic method used to solve systems of linear equations. It transforms a matrix into an upper triangular form, making it easier to solve using back substitution. The process involves three main operations: swapping the rows if necessary, multiplying a row by a non-zero constant, and adding or subtracting a multiple of one row to another row to eliminate a variable.
For example, in the given problem, the system of equations is first translated into an augmented matrix. Then, Gaussian Elimination transforms this matrix by performing row operations to clear out the variables below the leading ones in a column.
After simplifying the matrix to an upper triangular form, the solution can be found by back substitution, where variables are solved starting from the last row up to the first. This method is critical for solving linear systems efficiently, especially when dealing with a larger number of equations.
Newton-Raphson Method
The Newton-Raphson Method is a powerful technique used to find successively better approximations to the roots (or zeroes) of a real-valued function. It is especially useful for solving systems of nonlinear equations. The method involves iterations based on the derivative information of the function, hence requiring the calculation of the Jacobian for a system of equations.
The general formula used is: \[ x_{k+1} = x_k - J(x_k)^{-1}F(x_k) \]where \( x \) is the vector of unknowns, \( J(x) \) is the Jacobian matrix, and \( F(x) \) is the vector function of the system.
The Newton-Raphson method is known for its rapid convergence, but it is important to have a good initial guess to ensure convergence to the correct root. When applied to a system, each iteration involves solving a linear system, where the next approximation \( x_{k+1} \) is calculated. This method is favored for its precision and efficiency in computational applications.
Systems of Equations
Systems of equations involve finding values for unknown variables that satisfy multiple equations simultaneously. There are two main types: linear and nonlinear systems.
Linear systems are formed by linear equations, and can often be solved using methods like Gaussian Elimination or Matrix Algebra techniques. Nonlinear systems, conversely, consist of at least one nonlinear equation, necessitating iterative methods such as the Newton-Raphson Method.
In solving such systems, it is essential to determine the most appropriate method based on the nature (linear or nonlinear) and complexity of the system. Solutions can offer insights into various scientific and engineering problems, where multiple conditions must be satisfied concurrently.
Matrix Algebra
Matrix Algebra is a fundamental mathematical tool that deals with matrices and operations such as addition, subtraction, scalar multiplication, and multiplication of matrices. It forms the backbone of many numerical methods, including Gaussian Elimination.
An augmented matrix is often used to represent systems of linear equations. Matrix operations help streamline calculations that might otherwise be cumbersome.
Key concepts in matrix algebra include the computation of determinants, the inverse of matrices, and the rank, each playing crucial roles in solving systems of equations. Understanding these concepts is crucial as they provide a systematic approach to handle and solve sets of equations efficiently, enabling real-world applications in physics, engineering, and computer science.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Consider a large plane wall of thickness \(L=0.4 \mathrm{~m}\), thermal conductivity \(k=2.3 \mathrm{~W} / \mathrm{m} \cdot \mathrm{K}\), and surface area \(A=20 \mathrm{~m}^{2}\). The left side of the wall is maintained at a constant temperature of \(95^{\circ} \mathrm{C}\), while the right side loses heat by convection to the surrounding air at \(T_{\infty}=15^{\circ} \mathrm{C}\) with a heat transfer coefficient of \(h=18 \mathrm{~W} / \mathrm{m}^{2} \cdot \mathrm{K}\). Assuming steady one-dimensional heat transfer and taking the nodal spacing to be \(10 \mathrm{~cm},(a)\) obtain the finite difference formulation for all nodes, \((b)\) determine the nodal temperatures by solving those equations, and (c) evaluate the rate of heat transfer through the wall.

A common annoyance in cars in winter months is the formation of fog on the glass surfaces that blocks the view. A practical way of solving this problem is to blow hot air or to attach electric resistance heaters to the inner surfaces. Consider the rear window of a car that consists of a \(0.4\)-cm-thick glass \(\left(k=0.84 \mathrm{~W} / \mathrm{m} \cdot \mathrm{K}\right.\) and \(\left.\alpha=0.39 \times 10^{-6} \mathrm{~m}^{2} / \mathrm{s}\right)\). Strip heater wires of negligible thickness are attached to the inner surface of the glass, \(4 \mathrm{~cm}\) apart. Each wire generates heat at a rate of \(25 \mathrm{~W} / \mathrm{m}\) length. Initially the entire car, including its windows, is at the outdoor temperature of \(T_{o}=-3^{\circ} \mathrm{C}\). The heat transfer coefficients at the inner and outer surfaces of the glass can be taken to be \(h_{i}=6\) and \(h_{o}=20 \mathrm{~W} / \mathrm{m}^{2} \cdot \mathrm{K}\), respectively. Using the explicit finite difference method with a mesh size of \(\Delta x=\) \(0.2 \mathrm{~cm}\) along the thickness and \(\Delta y=1 \mathrm{~cm}\) in the direction normal to the heater wires, determine the temperature distribution throughout the glass \(15 \mathrm{~min}\) after the strip heaters are turned on. Also, determine the temperature distribution when steady conditions are reached.

Consider a 2-m-long and 0.7-m-wide stainless-steel plate whose thickness is \(0.1 \mathrm{~m}\). The left surface of the plate is exposed to a uniform heat flux of \(2000 \mathrm{~W} / \mathrm{m}^{2}\) while the right surface of the plate is exposed to a convective environment at \(0^{\circ} \mathrm{C}\) with \(h=400 \mathrm{~W} / \mathrm{m}^{2} \cdot \mathrm{K}\). The thermal conductivity of the stainless steel plate can be assumed to vary linearly with temperature range as \(k(T)=k_{o}(1+\beta T)\) where \(k_{o}=48 \mathrm{~W} / \mathrm{m} \cdot \mathrm{K}\) and \(\beta=9.21 \times 10^{-4}{ }^{\circ} \mathrm{C}^{-1}\). The stainless steel plate experiences a uniform volumetric heat generation at a rate of \(8 \times 10^{5} \mathrm{~W} / \mathrm{m}^{3}\). Assuming steady state one-dimensional heat transfer, determine the temperature distribution along the plate thickness.

The unsteady forward-difference heat conduction for a constant area, \(A\), pin fin with perimeter, \(p\), exposed to air whose temperature is \(T_{0}\) with a convection heat transfer coefficient of \(h\) is $$ \begin{aligned} T_{m}^{*+1}=& \frac{k}{\rho c_{p} \Delta x^{2}}\left[T_{m-1}^{*}+T_{m+1}^{*}+\frac{h p \Delta x^{2}}{A} T_{0}\right] \\\ &-\left[1-\frac{2 k}{\rho c_{p} \Delta x^{2}}-\frac{h p}{\rho c_{p} A}\right] T_{m}^{*} \end{aligned} $$ In order for this equation to produce a stable solution, the quantity \(\frac{2 k}{\rho c_{p} \Delta x^{2}}+\frac{h p}{\rho c_{p} A}\) must be (a) negative (b) zero (c) positive (d) greater than 1 (e) less than 1

How does the finite difference formulation of a transient heat conduction problem differ from that of a steady heat conduction problem? What does the term \(\rho A \Delta x c_{p}\left(T_{m}^{i+1}-T_{m}^{i}\right) / \Delta t\) represent in the transient finite difference formulation?

See all solutions

Recommended explanations on Physics Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.