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jak
jak
Last activity 5分 前

ere's a single MATLAB script addressing all the problems described:
matlab
% Problem 1: Simple if Statement
x = 5; % Example value
if x > 0
disp('The number is positive.');
end
% Problem 2: if ... else Statement
x = 7; % Example value
if mod(x, 2) == 0
disp('The number is even.');
else
disp('The number is odd.');
end
% Problem 3: if ... elseif ... else Statement
score = 85; % Example value
if score >= 90 && score <= 100
disp('Grade A');
elseif score >= 80 && score < 90
disp('Grade B');
elseif score >= 70 && score < 80
disp('Grade C');
elseif score >= 60 && score < 70
disp('Grade D');
else
disp('Grade F');
end
% Problem 4: Nested if Statement
x = 8; % Example value
if x > 0
if mod(x, 2) == 0
disp('The number is positive and even.');
else
disp('The number is positive and odd.');
end
end
% Problem 5: Temperature Classification (if ... elseif)
T = 18; % Example value
if T < 0
disp('Freezing');
elseif T >= 0 && T <= 15
disp('Cold');
elseif T >= 16 && T <= 25
disp('Mild');
else
disp('Hot');
end
% Problem 6: Simple switch Statement
grade = 'B'; % Example value
switch grade
case 'A'
disp('Excellent');
case 'B'
disp('Good');
case 'C'
disp('Fair');
case 'D'
disp('Poor');
case 'F'
disp('Fail');
otherwise
disp('Invalid grade.');
end
% Problem 7: Nested switch Statement
department = 'Engineering'; % Example value
major = 'Mechanical'; % Example value
switch department
case 'Engineering'
switch major
case 'Electrical'
disp('Electrical Engineering');
case 'Mechanical'
disp('Mechanical Engineering');
case 'Civil'
disp('Civil Engineering');
otherwise
disp('Unknown major.');
end
case 'Arts'
disp('Arts Department');
case 'Sciences'
disp('Sciences Department');
otherwise
disp('Unknown department.');
end
% Problem 8: Leap Year Check (if Statements)
year = 2024; % Example value
if mod(year, 4) == 0
if mod(year, 100) ~= 0 || mod(year, 400) == 0
disp('Leap year');
else
disp('Not a leap year');
end
else
disp('Not a leap year');
end
% Problem 9: Triangle Type (if ... elseif)
a = 5; b = 5; c = 5; % Example values
if a == b && b == c
disp('Equilateral triangle');
elseif a == b || b == c || a == c
disp('Isosceles triangle');
else
disp('Scalene triangle');
end
% Problem 10: Calculator with switch Statement
num1 = 10; % Example value
num2 = 5; % Example value
operation = '*'; % Example value
switch operation
case '+'
result = num1 + num2;
disp(['Result: ', num2str(result)]);
case '-'
result = num1 - num2;
disp(['Result: ', num2str(result)]);
case '*'
result = num1 * num2;
disp(['Result: ', num2str(result)]);
case '/'
if num2 ~= 0
result = num1 / num2;
disp(['Result: ', num2str(result)]);
else
disp('Error: Division by zero');
end
otherwise
disp('Invalid operation');
end
This code covers all the problems mentioned in your document. Replace the example values with inputs as needed.
% MATLAB Homework Solutions
% Problem 1: Sum of Even Numbers using while Loop
sum_even = 0;
num = 1;
while num <= 50
if mod(num, 2) == 0
sum_even = sum_even + num;
end
num = num + 1;
end
disp('Problem 1: Sum of Even Numbers');
disp(sum_even);
% Problem 2: Factorial Calculation using for Loop
n = 5; % Example number to calculate factorial
factorial_result = 1;
for i = 1:n
factorial_result = factorial_result * i;
end
disp('Problem 2: Factorial of the number');
disp(factorial_result);
% Problem 3: Multiplication Table using Nested Loops
disp('Problem 3: 10x10 Multiplication Table');
for i = 1:10
for j = 1:10
fprintf('%d\t', i * j);
end
fprintf('\n');
end
% Problem 4: Count Digits using while Loop
number = 12345; % Example number
digit_count = 0;
while number > 0
number = floor(number / 10);
digit_count = digit_count + 1;
end
disp('Problem 4: Number of digits');
disp(digit_count);
% Problem 5: Skip Multiples of 3 using for Loop and continue
disp('Problem 5: Numbers from 1 to 20 (skipping multiples of 3)');
for i = 1:20
if mod(i, 3) == 0
continue;
end
disp(i);
end
% Problem 6: Break a while Loop when Condition is Met
num = 101; % Start checking from 101
while true
if mod(num, 5) == 0 && mod(num, 7) == 0
disp('Problem 6: First number greater than 100 divisible by 5 and 7');
disp(num);
break;
end
num = num + 1;
end
% Problem 7: Summing Diagonal Elements using Nested Loops
matrix = randi([1, 20], 5, 5); % Create a 5x5 random matrix
diagonal_sum = 0;
for i = 1:5
diagonal_sum = diagonal_sum + matrix(i, i);
end
disp('Problem 7: Sum of diagonal elements');
disp(matrix); % Display the matrix
disp(diagonal_sum);
% Problem 8: Reverse a Number using while Loop
num = 12345; % Example number
reversed = 0;
while num > 0
remainder = mod(num, 10);
reversed = reversed * 10 + remainder;
num = floor(num / 10);
end
disp('Problem 8: Reversed number');
disp(reversed);
% Problem 9: Prime Number Checker using for Loop and break
num = 29; % Example number to check
is_prime = true; % Assume the number is prime
if num < 2
is_prime = false;
else
for i = 2:sqrt(num)
if mod(num, i) == 0
is_prime = false;
break;
end
end
end
disp('Problem 9: Is the number prime?');
disp(is_prime);
% Problem 10: Display Pascal's Triangle using Nested Loops
n = 5; % Number of rows in Pascal's Triangle
disp('Problem 10: Pascal''s Triangle');
for i = 0:n-1
row = 1; % First element in the row
for j = 0:i
fprintf('%d ', row);
row = row * (i - j) / (j + 1); % Calculate next element
end
fprintf('\n'); % Move to the next row
end
% MATLAB Homework: Matrix Solutions
%% 1. Create a 5x5 Matrix
A1 = reshape(1:25, 5, 5)'; % 5x5 matrix with elements 1 to 25 arranged row-wise
disp('1. 5x5 Matrix:');
disp(A1);
%% 2. Element Referencing
b = [10 20 30; 40 50 60; 70 80 90];
element = b(3,2); % Element in 3rd row, 2nd column
disp('2. Element Referencing (3rd row, 2nd column):');
disp(element);
%% 3. Column Vector Creation
v = b(:,1); % First column of matrix b
disp('3. Column Vector (1st column of b):');
disp(v);
%% 4. Sub-matrix Extraction
subMatrix = b(2:3, 1:2); % Last two rows, first two columns
disp('4. 2x2 Sub-Matrix:');
disp(subMatrix);
%% 5. Row Deletion
c = [1 2 3 4; 5 6 7 8; 9 10 11 12; 13 14 15 16];
c(2,:) = []; % Delete second row
disp('5. Matrix after Row Deletion:');
disp(c);
%% 6. Column Deletion
c(:,3) = []; % Delete third column
disp('6. Matrix after Column Deletion:');
disp(c);
%% 7. Matrix Addition and Subtraction
d = [1 2 3; 4 5 6; 7 8 9];
e = [9 8 7; 6 5 4; 3 2 1];
addResult = d + e; % Matrix addition
subResult = d - e; % Matrix subtraction
disp('7. Matrix Addition (d + e):');
disp(addResult);
disp('Matrix Subtraction (d - e):');
disp(subResult);
%% 8. Matrix Scalar Operations
scalarMultiply = d * 3; % Multiply by 3
scalarDivide = d / 3; % Divide by 3
disp('8. Matrix after Scalar Multiplication (d * 3):');
disp(scalarMultiply);
disp('Matrix after Scalar Division (d / 3):');
disp(scalarDivide);
%% 9. Matrix Transposition
f = [1 3 5; 2 4 6];
fTranspose = f';
disp('9. Transposed Matrix:');
disp(fTranspose);
%% 10. Matrix Inverse and Determinant
g = [1 0 2; 2 1 3; 3 4 1];
det_g = det(g); % Determinant
disp('10. Determinant of Matrix g:');
disp(det_g);
if det_g ~= 0
gInverse = inv(g); % Inverse of g
disp('Inverse of Matrix g:');
disp(gInverse);
else
disp('Matrix g is singular and does not have an inverse.');
end
%% 11. Dynamic Matrix Creation
n = input('Enter the size of the square matrix n: ');
A_dynamic = zeros(n,n);
for i = 1:n
for j = 1:n
A_dynamic(i,j) = i * j;
end
end
disp('11. Dynamic Square Matrix A (i*j):');
disp(A_dynamic);
%% 12. Checkerboard Matrix
n = 8; % Size of checkerboard matrix
checkerboard = mod((1:n)' + (1:n), 2); % Checkerboard logic
disp('12. Checkerboard Matrix (n=8):');
disp(checkerboard);
%% 13. Rotating a Matrix 90 Degrees Clockwise
M = [1 2 3; 4 5 6; 7 8 9]; % Test matrix
rotatedMatrix = M';
rotatedMatrix = flipud(rotatedMatrix);
disp('13. Rotated Matrix (90 Degrees Clockwise):');
disp(rotatedMatrix);
%% 14. Diagonal Dominance Validator
function isDominant = checkDiagonalDominance(X)
n = size(X, 1);
isDominant = true;
for i = 1:n
if abs(X(i,i)) <= sum(abs(X(i,:))) - abs(X(i,i))
isDominant = false;
break;
end
end
end
% Example: Test the diagonal dominance validator
matrixTest = [3 1 1; 1 4 1; 0 2 5];
disp('14. Diagonal Dominance Check:');
if checkDiagonalDominance(matrixTest)
disp('Matrix is diagonally dominant.');
else
disp('Matrix is NOT diagonally dominant.');
end
%% 15. Matrix Pattern Extraction (Cross Shape)
X = magic(7); % Create a 7x7 test matrix
middleRow = X(ceil(end/2), :);
middleColumn = X(:, ceil(end/2));
crossShape = [middleRow; middleColumn'];
disp('15. Extracted Cross Shape from Center of Matrix:');
disp('Middle Row:');
disp(middleRow);
disp('Middle Column:');
disp(middleColumn);
I'm beginning this MATLAB-based numerical methods class, and as I was thinking back to my previous MATLAB/Simulink classes, I definitely remember some projects more fondly than others. One of my most memorable was where I had to use MATLAB to analyze electrocardiogram (ECG) peaks. What about you guys? What are some of the best (or worst 🤭) MATLAB projects or assignments you've been given in the past?
Steve Eddins
Steve Eddins
Last activity 2024 年 12 月 12 日 21:25

Speaking as someone with 31+ years of experience developing and using imshow, I want to advocate for retiring and replacing it.
The function imshow has behaviors and defaults that were appropriate for the MATLAB and computer monitors of the 1990s, but which are not the best choice for most image display situations in today's MATLAB. Also, the 31 years have not been kind to the imshow code base. It is a glitchy, hard-to-maintain monster.
My new File Exchange function, imview, illustrates the kind of changes that I think should be made. The function imview is a much better MATLAB graphics citizen and produces higher quality image display by default, and it dispenses with the whole fraught business of trying to resize the containing figure. Although this is an initial release that does not yet support all the useful options that imshow does, it does enough that I am prepared to stop using imshow in my own work.
The Image Processing Toolbox team has just introduced in R2024b a new image viewer called imageshow, but that image viewer is created in a special-purpose window. It does not satisfy the need for an image display function that works well with the axes and figure objects of the traditional MATLAB graphics system.
I have published a blog post today that describes all this in more detail. I'd be interested to hear what other people think.
Note: Yes, I know there is an Image Processing Toolbox function called imview. That one is a stub for an old toolbox capability that was removed something like 15+ years ago. The only thing the toolbox imview function does now is call error. I have just submitted a support request to MathWorks to remove this old stub.
The int function in the Symbolic Toolbox has a hold/release functionality wherein the expression can be held to delay evaluation
syms x I
eqn = I == int(x,x,'Hold',true)
eqn = 
which allows one to show the integral, and then use release to show the result
release(eqn)
ans = 
I think I already submitted an enhancement request for the same functionality for symsum.
Maybe it would be nice to be able to hold/release any symbolic expression to delay the engine from doing evaluations/simplifications that it typically does. For example:
x*(x+1)/x, sin(sym(pi)/3)
ans = 
ans = 
If I'm trying to show a sequence of steps to develop a result, maybe I want to explicitly keep the x/x in the first case and then say "now the x in the numerator and denominator cancel and the result is ..." followed by the release command to get the final result.
Perhaps held expressions could even be nested to show a sequence of results upon subsequent releases.
Held expressions might be subject to other limitations, like maybe they can't be fplotted.
Seems like such a capability might not be useful for problem solving, but might be useful for exposition, instruction, etc.
Watt's Up with Electric Vehicles?EV modeling Ecosystem (Eco-friendly Vehicles), V2V Communication and V2I communications thereby emitting zero Emissions to considerably reduce NOx ,Particulates matters,CO2 given that Combustion is always incomplete and will always be.
Reduction of gas emissions outside to the environment will improve human life span ,few epidemic diseases and will result in long life standard
David
David
Last activity 2024 年 12 月 9 日 20:01

We will be updating the MATLAB Answers infrastructure at 1PM EST today. We do not expect any disruption of service during this time. However, if you notice any issues, please be patient and try again later. Thank you for your understanding.
adem
adem
Last activity 2024 年 12 月 16 日 23:02

Objectif : Etude d'une chaine de transmission numérique avec des turbo-codes combiné avec la technique HARQ (Hybrid Automatic Repeat reQuest):
* Mettre en place une chaîne de transmission numérique avec des turbo codes intégrant la technique HARQ.
* Évaluer les performances de cette chaîne, en termes de taux d'erreur et de débit sous diverses conditions de canal.
En structurant ainsi votre étude, vous pourrez mener une analyse approfondie des turbo codes et de la technique HARQ.
Outils : Utilisez des outils comme MATLAB, Simulink ou Python (avec des bibliothèques comme Scipy pour la modélisation des canaux et NumPy pour la gestion des calculs).
Simulations : Créez une série de simulations en variant les paramètres comme le SNR, le type de HARQ utilisé, etc.
Compétences développées : Maîtrise des techniques de détection et de correction d’erreurs pour améliorer la fiabilité des transmissions

Mike Croucher
Mike Croucher
Last activity 2024 年 12 月 6 日 22:32

Many of my best friends at MathWorks speak Spanish as their first language and we have a large community of Spanish-speaking users. You can see good evidence of this by checking out our relatively new Spanish YouTube channel which recently crossed the 10,000 subscriber mark
Mike Croucher
Mike Croucher
Last activity 2024 年 12 月 13 日 1:01

I've always used MATLAB with other languages. In the early days, C and C++ via mex files were the most common ways I spliced two languages together. Other than that I've also used MATLAB with Java, Excel and even Fortran.
In more recent years, Python is the language I tend to use most alongside MATLAB and support for this combination is steadily improving. In my latest blog post, I show how easy it has become to use Python's Numpy with MATLAB.
Have you used this functionality much? If so, what for? How well did it work for you?
David Ding
David Ding
Last activity 2024 年 12 月 10 日 19:51

I am inspired by the latest video from YouTube science content creator Veritasium on his distinct yet thorough explanation on how rainbows work. In his video, he set up a glass sphere experiment representing how light rays would travel inside a raindrop that ultimately forms the rainbow. I highly recommend checking it out.
In the meantime, I created an interactive MATLAB App in MATLAB Online using App Designer to visualize the light paths going through a spherical raindrop with numerical calculations along the way. While I've seen many diagrams out there showing the light paths, I haven't found any doing calculations in each step. Hence I created an app in MATLAB to show the calculations along with the visualizations as one varies the position of the incoming light ray.
Demo video:
For more information about the app and how to open it and play around with it in MATLAB Online, please check out my blog article:
Image Analyst
Image Analyst
Last activity 2024 年 12 月 5 日 5:43

Toshiaki Takeuchi
Toshiaki Takeuchi
Last activity 2024 年 12 月 3 日 22:30

Our MathWorks Usability Team is working on an accessibility project and they want to interview people who use MATLAB and also have experience with screen readers.
If you fit the criteria and are interested, sign up here https://www.mathworks.com/products/usability.html?tfa_30=A11Y
Steve Eddins
Steve Eddins
Last activity 2024 年 12 月 3 日 2:20

I wish I knew more about the intended evolution of the capabilities of the function arguments block. I love implementing function syntaxes using this relatively new form, but it doesn't yet handle some function syntax design patterns that I think are valuable and worth keeping.
For example, some functions take an input quantity that can something numeric, or it can be an option string that descriptively names a particular value of that quantity. One example is dateshift(t,"dayofweek",dow), where dow can be an integer from 1 to 7, or it can be one of the option strings "weekday" or "weekend".
Another example is Image Processing Toolbox that take a connectivity specifier as input. The function bwconncomp is one particular case. Connectivity can be specified using certain scalars, certain arrays, or the option string "maximal".
I think this is a worthwhile function design pattern, but I don't think the arguments block validation functionality supports it well (unless you use a lot of extra code that duplicates standard MATLAB behavior, which undermines the value of the arguments block).
I posted about this today over on my blog. See "Function Syntax Design Conundrum."
MathWorkers - believe me, I know that it is not in your DNA to discuss future features. But would anyone care to offer a hint about directions for the arguments block functionality?
I am very excited to share my new book "Data-driven method for dynamic systems" available through SIAM publishing: https://epubs.siam.org/doi/10.1137/1.9781611978162
This book brings together modern computational tools to provide an accurate understanding of dynamic data. The techniques build on pencil-and-paper mathematical techniques that go back decades and sometimes even centuries. The result is an introduction to state-of-the-art methods that complement, rather than replace, traditional analysis of time-dependent systems. One can find methods in this book that are not found in other books, as well as methods developed exclusively for the book itself. I also provide an example-driven exploration that is (hopefully) appealing to graduate students and researchers who are new to the subject.
Each and every example for the book can be reproduced using the code at this repo: https://github.com/jbramburger/DataDrivenDynSyst
Hope you like it!
Image Analyst
Image Analyst
Last activity 2024 年 12 月 2 日 22:14

Christmas season is underway at my house:
(Sorry - the ornament is not available at the MathWorks Merch Shop -- I made it with a 3-D printer.)
Is it possible to differenciate the input, output and in-between wires by colors?
Walter Roberson
Walter Roberson
Last activity 2024 年 12 月 16 日 23:04

At the present time, the following problems are known in MATLAB Answers itself:
  • Symbolic output is not displaying. The work-around is to disp(char(EXPRESSION)) or pretty(EXPRESSION)
  • Symbolic preferences are sometimes set to non-defaults
  • files get attached as .html and cannot be read from Answers
Chen Lin
Chen Lin
Last activity 2024 年 12 月 7 日 7:25

Hello, MATLAB fans!
For years, many of you have expressed interest in getting your hands on some cool MathWorks merchandise. I'm thrilled to announce that the wait is over—the MathWorks Merch Shop is officially open!
In our shop, you'll find a variety of exciting items, including baseball caps, mugs, T-shirts, and YETI bottles.
Visit the shop today and explore all the fantastic merchandise we have to offer. Happy shopping!