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 Vaia!

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

What happens to the discretization and the round-off errors as the step size is decreased?

Consider a long concrete dam \((k=0.6 \mathrm{~W} / \mathrm{m} \cdot \mathrm{K}\), (es \(\alpha_{s}=0.7\) ) of triangular cross section whose exposed surface is subjected to solar heat flux of \(\dot{q}_{s}=\) \(800 \mathrm{~W} / \mathrm{m}^{2}\) and to convection and radiation to the environment at \(25^{\circ} \mathrm{C}\) with a combined heat transfer coefficient of \(30 \mathrm{~W} / \mathrm{m}^{2} \cdot \mathrm{K}\). The \(2-\mathrm{m}\)-high vertical section of the dam is subjected to convection by water at \(15^{\circ} \mathrm{C}\) with a heat transfer coefficient of \(150 \mathrm{~W} / \mathrm{m}^{2} \cdot \mathrm{K}\), and heat transfer through the 2-m-long base is considered to be negligible. Using the finite difference method with a mesh size of \(\Delta x=\Delta y=1 \mathrm{~m}\) and assuming steady two-dimensional heat transfer, determine the temperature of the top, middle, and bottom of the exposed surface of the dam.

Consider a medium in which the finite difference formulation of a general interior node is given in its simplest form as $$ T_{\text {node }}=\left(T_{\text {left }}+T_{\text {top }}+T_{\text {right }}+T_{\text {bottom }}\right) / 4 $$ (a) Is heat transfer in this medium steady or transient? (b) Is heat transfer one-, two-, or three-dimensional? (c) Is there heat generation in the medium? (d) Is the nodal spacing constant or variable? (e) Is the thermal conductivity of the medium constant or variable?

Can the global (accumulated) discretization error be less than the local error during a step? Explain.

Consider an aluminum alloy fin \((k=180 \mathrm{~W} / \mathrm{m} \cdot \mathrm{K})\) of triangular cross section whose length is \(L=5 \mathrm{~cm}\), base thickness is \(b=1 \mathrm{~cm}\), and width \(w\) in the direction normal to the plane of paper is very large. The base of the fin is maintained at a temperature of \(T_{0}=180^{\circ} \mathrm{C}\). The fin is losing heat by convection to the ambient air at \(T_{\infty}=25^{\circ} \mathrm{C}\) with a heat transfer coefficient of \(h=25 \mathrm{~W} / \mathrm{m}^{2} \cdot \mathrm{K}\) and by radiation to the surrounding surfaces at an average temperature of \(T_{\text {surr }}=290 \mathrm{~K}\). Using the finite difference method with six equally spaced nodes along the fin in the \(x\)-direction, determine \((a)\) the temperatures at the nodes and \((b)\) the rate of heat transfer from the fin for \(w=1 \mathrm{~m}\). Take the emissivity of the fin surface to be \(0.9\) and assume steady one-dimensional heat transfer in the fin.

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.

Sign-up for free