## How do I do that in MATLAB

HOW DO I DO THAT IN MATLAB SERIES?

## How to PUBLISH in MATLAB

This is how you can get your mfile published.

Click anywhere in the mfile (if your cursor is not in the mfile, you may not get the proper menu open)

-> Go to PUBLISH
-> Click on Down Black Arrow under Publish
-> Choose Edit Publishing Option
-> click on Output file format and the right column entry will show html, but if you click on html, you will get a drop-down box as shown in the figure below.  Choose your option.

You can click on the figure below to see a larger version of the figure.

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• Holistic Numerical Methods Open Course Ware:
• the textbooks on
• the Massive Open Online Course (MOOCs) available at

## Ability to break long fprintf statements

Problem:
A student sent me an email – ” I can’t figure out how to continue my text on another line in the editor while using the fprintf command in MATLAB.  It seems like this should be something simple, but I can’t figure it out.  The closest thing I have tried is:
fprintf(‘filler filler filler’, …
‘filler filler’)

When I run this script, this only displays the content within the first set of quotes though.

Solution:
Assign the long strings to variables, and then use the fprintf statements

abc=’My name is’
def=’ Slim Shady, also known as Marshall Mathers’
fprintf([abc def])

or you could do the following, especially if you have other non-string variables to print

abc=’My name is’
def=’ Slim Shady, also known as Marshall Mathers’
fprintf(‘%s %s’,abc,def)

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This post is brought to you by

• Holistic Numerical Methods Open Course Ware:
• the textbooks on
• the Massive Open Online Course (MOOCs) available at

## How do I solve simultaneous linear equations given in equation form? Updated Matlab 2018b

Guest co-blogger: : Luis Serrano

Many students ask me how do I do this or that in MATLAB.  So I thought why not have a small series of my next few blogs do that.  In this blog, I show you how to solve simultaneous linear equations given in equation form.

• The MATLAB program link is here.
• The HTML version of the MATLAB program is here.
• DO NOT COPY AND PASTE THE PROGRAM BELOW BECAUSE THE SINGLE QUOTES DO NOT TRANSLATE TO THE CORRECT SINGLE QUOTES IN MATLAB EDITOR.  DOWNLOAD THE MATLAB PROGRAM INSTEAD

%% SUMMARY
% Language : Matlab 2018b;
% Authors : Autar Kaw and Luis Serrano;
% Mfile available at
% http://nm.mathforcollege.com/blog/SimultaneousEquationsEqForm.m;
% Last Revised : January 22, 2020;
% Abstract: This program shows you how to solve a set of
% simultaneous linear equations given in equation form?
% .
clc
clear all
%% INTRODUCTION
disp(‘ABSTRACT’)
disp(‘ This program shows you how to solve a’)
disp(‘ set of simultaneous linear equations given in equation form’)
disp(‘ ‘)
disp(‘AUTHOR’)
disp(‘ Autar Kaw and Luis Serrano’)
disp(‘ ‘)
disp(‘MFILE SOURCE’)
disp(‘ http://nm.mathforcollege.com/blog/SimultaneousEquationsEqForm.m&#8217;)
disp(‘ ‘)
disp(‘LAST REVISED’)
disp(‘ January 22, 2020’)
disp(‘ ‘)
%% INPUTS
% Enter the equations
syms a b c
eqn1=12*a+23*b+39*c==29
eqn2=13*a+17*b+19*c==37
eqn3=21*a+23*b+29*c==59
%% DISPLAYING INPUTS
disp(‘ ‘)
disp(‘INPUTS’)
disp(‘________________________’)
disp(‘Equations’)
disp(‘________________________’)
disp(eqn1)
disp(eqn2)
disp(eqn3)
%% THE CODE
% The solution
X=solve(eqn1,eqn2,eqn3);
% Assigning the output
a=double(X.a);
b=double(X.b);
c=double(X.c);
%% DISPLAYING OUTPUTS
disp(‘ ‘)
disp(‘OUTPUTS’)
disp(‘________________________’)
disp(‘Solution Vector’)
disp(‘________________________’)
fprintf(‘\nValue of a= %g’,a)
fprintf(‘\nValue of b= %g’,b)
fprintf(‘\nValue of c= %g’,c)
disp(‘ ‘)
disp(‘________________________’)

_______________________

This post is brought to you by

• Holistic Numerical Methods Open Course Ware:
• the textbooks on
• the Massive Open Online Course (MOOCs) available at

## How do I solve a nonlinear equation that needs to be setup – Updated to MATLAB 2018b

Guest co-blogger: Luis Serrano

Many students ask me how do I do this or that in MATLAB. So I thought why not have a small series of my next few blogs do that. In this blog, I show you how to solve a nonlinear equation that needs to be set up.

For example to find the depth ‘x’ to which a ball is floating in water is based on the following cubic equation
4*R^3*S=3*x^2*(R-x/3)
where
S= specific gravity of ball
So how do we set this up if S and R are input values?

The MATLAB program link is here.

The HTML version of the MATLAB program is here.

• DO NOT COPY AND PASTE THE PROGRAM BELOW BECAUSE THE SINGLE QUOTES DO NOT TRANSLATE TO THE CORRECT SINGLE QUOTES IN MATLAB EDITOR.  DOWNLOAD THE MATLAB PROGRAM INSTEAD

%% SUMMARY
% Language : Matlab 2018b;
% Authors : Autar Kaw and Luis Serrano;
% Mfile available at
% http://nm.mathforcollege.com/blog/NonlinearEquations_withSetUp.m;
% Last Revised : January 22, 2020;
% Abstract: This program shows you how to solve a nonlinear equation
% that needs to set up as opposed that is just given to you.
clc
clear all
%% INTRODUCTION
disp(‘ABSTRACT’)
disp(‘ This program shows you how to solve’)
disp(‘ a nonlinear equation that needs to be setup’)
disp(‘ ‘)
disp(‘AUTHORS’)
disp(‘ Autar Kaw and Luis Serrano’)
disp(‘ ‘)
disp(‘MFILE SOURCE’)
disp(‘ http://nm.mathforcollege.com/blog/NonlinearEquations_withSetUp.m&#8217;)
disp(‘ ‘)
disp(‘LAST REVISED’)
disp(‘ January 22, 2020’)
disp(‘ ‘)
%% INPUTS
% Solve the nonlinear equation where you need to set up the equation
% For example to find the depth ‘x’ to which a ball is floating in water is based on the following
% cubic equation 4*R^3*S=3*x^2*(R-x/3) R= radius of ball S= specific gravity of ball So how do we set this up if S and R are input values
S=0.6
R=0.055
%% DISPLAYING INPUTS
disp(‘INPUTS’)
func=[‘ The equation to be solved is 4*R^3*S=3*x^2*(R-x/3)’];
disp(func)
disp(‘ ‘)
%% THE CODE
% Define x as a symbol
syms x
% Setting up the equation
C1=4*R^3*S
C2=3*x^2*(R-x/3)
f=C1==C2
% Finding the solution of the nonlinear equation
soln=vpasolve(f,x);
solnvalue=double(soln);
%% DISPLAYING OUTPUTS
disp(‘OUTPUTS’)
for i=1:1:length(solnvalue)
fprintf(‘\nThe solution# %g is %g’,i,solnvalue(i))
end
disp(‘ ‘)

________________________

This post is brought to you by

• Holistic Numerical Methods Open Course Ware:
• the textbooks on
• the Massive Open Online Course (MOOCs) available at

## Third Edition of Programming Textbook

We have just published the third edition of the textbook on programming with MATLAB.   It is available for purchase at http://www.lulu.com/shop/autar-kaw-and-benjamin-rigsby-and-ismet-handzic-and-daniel-miller/introduction-to-programming-concepts-with-matlab-third-edition/paperback/product-24333322.html

The book is intended for an introductory course in programming in STEM (science, technology, engineering, and mathematics) fields while using MATLAB as the programming language. MATLAB is a popular computational software package used in universities and industries alike.

This textbook differentiates itself from others in two specific ways.

1. The textbook is suitable for the many engineering departments throughout the nation that no longer teach a 3-credit hour programming course. They weave programming and mathematical software packages such as MATLAB in courses such as Foundations of Engineering, Freshmen Design, Modeling of Systems, Engineering Analysis, Numerical Methods, etc. This book is highly suitable for such audiences. To achieve these goals and make the access far-reaching, we have been deliberate in keeping the lessons short in length so that instructors can easily choose the course content in a modular way.
2. The textbook is a stand-alone resource for learning programming where the lectures complement the textbook rather than vice versa. This is because of the reason above where in-classroom time is truncated, and therefore students need to be more self-taught. For this reason, we have been meticulous when selecting and organizing the textbook content to include fundamental and application programming problems that prepare students well for other problems they will solve in academia and industry.

The book has nine modules which have been each broken down by lessons. There are 42 lessons in all and depending on the learning outcomes of the course, an instructor can choose to assign only necessary lessons. Modules 1-3 focus on MATLAB and programming basics like the MATLAB program interface, programming variables, different types of data, debugging, plotting, and applications to science and engineering problems. In Module 4, we show the use of MATLAB for basic mathematical procedures learned in the engineering courses including nonlinear equations, integration, differentiation, simultaneous linear equations, interpolation, regression, and ordinary differential equations. In Modules 5-8, the user is introduced to basic programming concepts of conditional statements, repetition (loops), and custom functions. In Module 9, program input/output is shown with writing to and reading from external files as well as navigating directories with MATLAB. Important appendices include a primer on matrix algebra, a collection of mini-projects, and a introduction to animating plots in MATLAB. Appendix A provides a primer on matrix algebra. Appendix B contains a set of mini-projects. Appendix C demonstrates how to make animated plots in MATLAB.

Each lesson contains screenshots of actual MATLAB programs that are used to help illustrate the concepts presented. More than 120 complete programs are shown throughout this book to demonstrate to the reader how to use programming concepts. The book is written in a USA-Today style question-answer format for a quick grasp of the concepts.

The purpose of this book is to provide the reader with a firm basic understanding of MATLAB syntax and fundamental programming concepts. Each lesson contains MATLAB programs that are used to help illustrate the concepts presented. By no means do the authors claim to present every MATLAB command, function, application, or programming concept in existence.

## Reducing ordinary differential equations to state variable matrix form

To be able to solve differential equations numerically, one has to reduce them to a set of first order ordinary differential equations – also called the state variable form.  By writing them in a matrix form, the equations become conducive for programming in languages such as MATLAB.  Here is an example of this reduction to state variable matrix form.

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• Holistic Numerical Methods Open Course Ware:
• the textbooks on
• the Massive Open Online Course (MOOCs) available at

## Unexpected zeros error in MATLAB in zeros function

YouTube Comment: This MATLAB program gives me an error.  W=2.4; L=3; Delta=0.6; i=(W./Delta)+2; j=(L./Delta); T=zeros(i,j); . When I write 0.1 for Delta, there is an error for zeros statement.

Answer: When writing a new program, avoid using the semicolon as it suppresses the output. Write each line separately in a .m file and run the mfile. That way you would have noticed that “i” is turning out to be a real number. It shows up as 26.0000 but if you use format long statement, you will see that you get 25.999999999999996. You can round(i) and round(j) to the nearest integer. The reason “i” turns out to be 25.999999999999996 is because of roundoff error, as numbers and calculations get represented in binary format.

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This post is brought to you by

• Holistic Numerical Methods Open Course Ware:
• the textbooks on
• the Massive Open Online Course (MOOCs) available at

## Checking if a number is non-negative or not?

Many students ask me how do I do this or that in MATLAB.  This is a new addition to the “How do I do that in MATLAB“  series.

In this blog, I show you how to use the if-else-end statement to write a simple program of finding if a number is non-negative or not.

Here are the links for the program.
The mfile is here
The published version of the mfile is here

%% HOW DO I DO THAT IN MATLAB SERIES?
% In this series, I am answering questions that students have asked
%% TOPIC
% How do I check if a number is non-negative or negative
%% SUMMARY
% Language : Matlab 2010a;
% Authors : Autar Kaw and Sri Harsha Garapati;
% Mfile available at
% http://nm.mathforcollege.com/blog/if_else_end_statements_blog.m
% Last Revised : January 23, 2012;
% Abstract: This program shows you how to check if a number is negative or
% non-negative using if-else-end statement in MATLAB
clc
clear all
%% INTRODUCTION

disp(‘ABSTRACT’)
disp(‘   This program shows you how to check if a number is negative or’)
disp(‘   non-negative using if-else-end statement in MATLAB’)
disp(‘ ‘)
disp(‘AUTHOR’)
disp(‘   Autar Kaw and Sri Harsha Garapati of https://autarkaw.wordpress.com’)
disp(‘ ‘)
disp(‘MFILE SOURCE’)
disp(‘   http://nm.mathforcollege.com/blog/if_else_end_statements_blog.m’)
disp(‘ ‘)
disp(‘LAST REVISED’)
disp(‘   February 13, 2012’)
disp(‘ ‘)

%% INPUTS

% Enter the number to be tested
a=4;
%% DISPLAYING INPUTS
disp(‘  ‘)
disp(‘INPUTS’)

% Printing the input number
fprintf(‘The input number to be tested is %g\n’,a)
%% CODE AND DISPLAYING OUTPUT
disp(‘  ‘)
disp(‘OUTPUTS’)

% using the if-else-end statement to check
if (a>=0)
disp(‘The number is nonnegative’)
else
disp(‘The number is negative’)
end

_________________________________________________

This post is brought to you by Holistic Numerical Methods: Numerical Methods for the STEM undergraduate at http://nm.mathforcollege.com, the textbook on Numerical Methods with Applications available from the lulu storefront, the textbook on Introduction to Programming Concepts Using MATLAB, and the YouTube video lectures available at http://nm.mathforcollege.com/videos.  Subscribe to the blog via a reader or email to stay updated with this blog. Let the information follow you.

## Printer cuts off MATLAB code and text

When you print MATLAB code or the published form of the code, you may find the code or the comments getting cut off.  The solution to these problems is given at several places in MATLAB blogs and documentation.  In this blog, I have summarized what to do as the issues of code getting cut off falls into three categories

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This post is brought to you by Holistic Numerical Methods: Numerical Methods for the STEM undergraduate at http://nm.mathforcollege.com, the textbook on Numerical Methods with Applications available from the lulu storefront, the textbook on Introduction to Programming Concepts Using MATLAB, and the YouTube video lectures available at http://nm.mathforcollege.com/videos.  Subscribe to the blog via a reader or email to stay updated with this blog. Let the information follow you.