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Extracting elements common to rows and columns in a matrix
M = your matrix result = M([3,5],4:5) The [3,5] syntax is simply a vector with the indexes specified in any order. They don't...

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Peobelms about matrix dimensions
Take a look at this term: exp(-1*E./T.). Looks like you have too many periods in this part of the calculation. Try this exp(...

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ode45 For Three Functions
You made a good start, but you need to solve these differential equations simultaneously. That will mean you need to work with ...

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Bitwise "AND" logic operator not giving accurate results!!!
MATLAB is case sensitive. powersof2 and powersOf2 are different variables. Use the same case for both.

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Convert C++ to Mex
See the input( ) function for getting the inputs from the user. Then see the fprintf( ) function for displaying formatted outpu...

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Compiling MEX files that use IMSL Numerical Libraries
Something like this should get you close: mwPointer plhs(*), prhs(*) mwPointer, external :: mxGetM, mxGetN, mxGetPr, mxCreateD...

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the use of eye command?
eye(M,N) creates an MxN matrix with 1's along the main diagonal (from the upper left corner down towards lower right) and 0's ev...

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Euler, Runge Kutta, and ODE45
You could use a switch control block to run the method selected. https://www.mathworks.com/help/matlab/ref/switch.html?s_tid=sr...

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How to fix time step ?
Your function handles are functions of t, so you need to be passing in t, not n. E.g., if t(n)<5 speed0(n) = spe...

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I'm not sure why my code is working. It is for a projectile rocket that has water, so need to take into account water thrust and drag to find the distance travelled. The code is below:
Some quick observations: This t=t+i*dt; should be this t(i+1) = t(i) + dt; Your indexing appears to be incorrect also. You...

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Subscript indices must either be real positive integers or logicals.
This line produces indexes of zeros: for a = zeros(1, Nmax-1) I think you meant this instead: g = zeros(1, Nmax); for a = 1:...

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sort an array without using the command sort
Instead of using find, you could just have the min( ) function return the index to you. And then delete that element. [v1(...

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Reshape does not Use the Columns I Want
For your posted example, simply [x(:,1:2);x(:,3:4)] But this begs the question, what is your real problem and what sizes can x...

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Basic math operations on contents of a cell array
I suppose only TMW could give you their reasons for not implementing numeric operations on cell arrays. Maybe they simply didn'...

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Triangular pulse with function handle t(@)
If you must use a one-liner function handle, the general form could be this: f = @(t) (t >= 0).*(t < pulseDuration/2).*(express...

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Output to an array or matrix
Colon operator. A = 1:5;

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What are all the possible combinations given the restrictions?
Buy any item in January and any other item in the other month. All combinations are valid and within the $8 budget so essential...

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Function takes as input two nonempty matrices A and B and returns the product AB
This is a matrix multiply, so you need to keep the rows and columns of the inputs separately. E.g., [NRowsA,NColsA] = size(A);...

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Roll a die until n consecutive rolls have the same value
You made a good start, but it might help to change your inner while loop exit condition to be exactly what you are looking for ....

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Solve function give 2 answers when there should be 1.
For a generic orbit problem, i.e. an ellipse, there are always going to be two places on the orbit path with the same r value (e...

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MatLab While loop indexing?
Add a counter to your loop. Initialize the counter to 0 and add 1 to it within the loop. E.g., counter = 0; % other stuff w...

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Extracting a submatrix based on conditions on first columns of a big matrix
BigMatrix = your big matrix BigMatrix1 = BigMatrix(:,1); % 1st column x = BigMatrix1 > 527 & BigMatrix1 < 580; % logical index...

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Can someone help me figure out what is wrong with my function c1 = ult_trid(m,b) ??
d is a 4x1 vector and you are trying to access the d(4,4) element, hence the error.

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Question about numerical integration for cos vs cosd
By hand: int cosd(theta) = int cos(theta*pi/180) = sin(theta*pi/180)*180/pi Integrated from 0 to 15 degrees: sin(15*pi/180)...

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Error: File: d3.m Line: 7 Column: 10 Invalid use of operator.
Looks like you are missing some variable names and some matching parentheses in this line: scatter((:,1)),(:,2)),'o')

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Please help me write the f function in matlab
I would assume from the equation image that the exp( ) stuff maybe should be outside of the sin( ) stuff. E.g., f = 2.*x.*sin(...

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How to create multiple matrices with different sizes without a loop?
You will either need to use loops, or hide the loops behind a function call (e.g., arrayfun): result = arrayfun(@(x)randi([0 x]...

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Inserting a column in a matrix before adding it to another matrix in a loop
C = [A,[B1;B2;B3]];

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I need help solving a equation with the Runge-Kutta-Fehlberg adaptive step size method using ode45.
For Problem 2 and Problem 3, you should not be looping over any variables. You simply have a derivative function that you pass ...

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Wrapper to run 32-Bit mex files on 64-Bit MATLAB
32-bit mex files are not standalone code. They interact with 32-bit MATLAB library code which interacts with the 32-bit MATLAB ...

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