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linear equation cant solve
Like so rcd = [-1, - 1, 2] ; ucd = rcd/norm(rcd); syms Ax Ay Az Bx Bz T ; eqn1 = [Ax Ay Az]+[0 0 -2*50*9.80665]+[Bx 0 Bz]+ ...

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what y(2) ,y(3), y(4) , y(5) ,by using matlab ?
You need to start with y(1) = 1, not y(0) = 1. Then with y(2) = 5, you can use a for loop: for n=1:3, y(n+2) = 3*y(n+1)-5*y(n)...

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why does ode45 happen this index error?
See the following: global d; d=1; tspan=[0;0.05]; xi=[1;2;pi]; vk=[3;5]; [t,y]=ode45(@TwoWheel2,tspan,xi,[],vk); function...

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plotting multiple vectors on one graph
Like this perhaps: >> x = 1:5; >> plot(x,y1,'o-',x,y2,'*-',x,y3,'s-')

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Find temperature vector using finite difference method
Try this L = 2; N = 250; T0 = 300; % boundary condition Tend = 400; % boundary condition h = L/N; xj = 0:h:L; %%%%%%%%%%%...

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for loop to repeat specified number of times
If M is your 40448x20 matrix then something like for i = 1:9:40448 K = M(i:i+8,:); ... other calculations with ...

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Index exceeds the number of array elements (1).
You should put x_rec = zeros(1000,1); y_rec = zeros(1000,1); just before x_rec(1)=x(1); y_rec(1)=y(1);

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Error in solving differential of spherical Bessel function. How to solve it?
Assuming fcntr is a vector of values then you need lambda0=c0 ./ fcntr; and fnh=@(r1)(diff(sqrt(pi ./ (2*k1a*r1)) .* besselh...

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Find Optimum Temperature where Concentration of product vs Time is high.
Does this help: tspan = 0:0.1:3; C0 = [1.; 0]; T = 330:5:360; for i = 1:numel(T) [t,C]=ode45(...

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Matrix condition in while loop
I don't know if this solves your problem, but while (abs(EP(i+1,:)-EP(i,:)>0.1)) should probably be while abs(EP(i+1,:)-EP(i,...

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ode45 coupled first degree ODEs
Do you mean something like this: [v, z] = ode45(@myode,[0 40],[2 6]); plot(v,z) function dz = myode(~,z) a = 0.4; b = 0.0...

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Here is my code where I am solving the initial value problem dy/dt = -3y+1. I am getting an error for the ynum(n+1) equation : Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimi
You haven't defined the RHS2 function!

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How to use if statements and for loop to plot the following series?
Try replacing if (j == t) with if (mod(j,2)==1) and if (j == d) with if (mod(j,2)==0)

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The force on a cylinder near a wall in viscous potential flows
Here is Cx for you: >> bovera = 1.001:0.2:10; >> Cx = 1./(sqrt(bovera.^2-1)*2*pi); >> plot(bovera,Cx,'o'),grid (Note that Cx...

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Unrecognized function or variable 'x'.
To avoid your error message simply specify the derivatives directly (they are easy to obtain from polynomials). With both initi...

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Solving 4th order ode using ode45
Here's some coding that basically solves the equation. I've no idea what the value of k should really be, but the constants cho...

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Solving two dependent two variable ordinary differential equation
Here's the basic syntax. Look up ode45 in the documentation for more detail. tspan = [0 2]; y0 = [0, 0]; [t, y] = ode45(@r...

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Error While running a while loop (index exceeds number of array elements)
for j = 1:(i-1) when i = 1 this will lead to a j index of zero. Matlab only likes indices of 1 and greater.

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problem ode45 system of differential equation
This works (I think your value of C is not in the right units): tSpan=[0 2.33e9]; y0=[8.6e7 0 0 55.1]; [tSol,ySol]=ode45(@com...

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Making a 'progressive' plot from a scattered matrix.
Look up cumtrapz

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Need help on difficulty 3D Plot. - Problem resolved
Here's some code to get you started % Data T=300; k=1.38064852e-23; Ea=7.2*10^(-21); Ed=7.2*10^(-21); Nv=2.5*10^(25)*((0.5...

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"find" data range within vector and ensure second index greater than first
How about y = find(A(max(x):end)<3);

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Plotting a function with a for loop to have a special scenario for dividing by 0
Try t = -10:0.01:10; for i = 1:length(t) if t(i) ==0 y(i)=1; else y(i) = sin...

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Estimate r and K of logistic curve
Since y is your data you first need to invert the data to get z. Then you need to take ln(z) if you want to see a roughly strai...

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How to create a vector and populate it with the first 10 roots using this Newtons method code?
Something more like this perhaps (no need for symbolic maths). f = @(x) x.*tan(x)-0.1; %Function g = @(x) x.*tan(x).^2 + ta...

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I have no idea how to start this question
Look at https://uk.mathworks.com/matlabcentral/answers/591166-loop-answers-slightly-out-from-correct-values .

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How to speed up the iteration of the for loop and make some further improvement on the below code?
The following, which makes use of fzero to find the value of c that makes F_total equal to zero, runs a lot faster. I've no ide...

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How to solve problems with ODE in my SIR model?
Replace y = ode45("epidemia", [0 60], [495; 5; 0]); by y = ode45(@epidemia, [0 60], [495; 5; 0]);

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Solving Exponential equation with data
Try a = 0.0093; b = 0.0095; c = 0.0035; d = 0.00185; f = a*(1 - exp(-b*x)) + c*(exp(d*x) - 1); plot(x,y,'o',x,f),grid xlabel...

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I am attempting to plot data from an experiment and compare it to a numerical model
Plot as follows. This also gives you the root sum square (RSS) errors x = linspace(3, 4, 5); expmdot_339 = [5.16e-2 1.83e-3...

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