Alan Stevens
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650 total contributions since 2020
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Awarded to Alan Stevens on 25 May 2020
help for projectile equation
These are the equations (note that theta is measured from the horizontal, and is positive in the anticlockwise direction): ...
1 day ago | 0
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How to sum part of a matrix using loop command
Try replacing B(k1,k2) = sum(A(k1,k2:3:end),2); by B(k1,k2) = sum(A(k1,k2:35:end),2);
1 day ago | 0
Problem using ode23tb (Error: Index exceeds the number of array elements)
Must be something to do with the nested functions! It works when structured as follows: [t,y] = ode23tb(@yfn,[0 pi/(10e6*pi)],[...
3 days ago | 0
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4th order Runge-Kutta Problem in Special ranges
Change y(0) = -1; to y(1) = -1; Matlab indices start at 1 not zero.
3 days ago | 1
how to find the period for the 0.2s,0.8s,1s and 2s ?
You need to change the size of the vectors etc appropriately. For example, for period = 0.2 you could have T1 = 0.01; t1 = 0:...
3 days ago | 0
How to create a new variable in each iteration of the for loop?
One way as follows: y = 1024; %for example winSize=[16,64,256,1024,4096]; for i = 1:numel(winSize) if winSize(i) == 16 ...
4 days ago | 0
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Non-Linear Coupled First-Order ODEs (with multiple derivative terms in each equation).
These ode's can be rearranged as follows: As long as you know initial values for a, b and c, then given that you know everyth...
5 days ago | 0
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How can i make the integral curves?
Like so? [x,y] = meshgrid(1:0.5:6,-3:0.5:2); u = ones(size(x)); v = (x.*y+y.^3)/2*x.^2; r = sqrt(u.^2 + v.^2); plot([0,0],[...
6 days ago | 0
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Convert one matrix to two matrices with the order of the initial matrix
Try r1 = r; r1(:,2:2:end) = 0; r2 = r; r2(:,1:2:end) = 0;
6 days ago | 1
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How to clump/consolidate values together using the mean function
Here's one way cw = 4; %cell width a = 1:8; b = (1:8)'; c = a.*b; mat=ones(8,8); %temporary matrix avfn = @(m) mean(m,'A...
6 days ago | 0
solve non linear equations
Add these lines at the end to get the values of S and J Soln = vpasolve([eqn1, eqn2],[S, J],[1 1]); disp(Soln.S) disp(Soln.J)...
6 days ago | 0
How to find an unknown in an integral equation
Here's one way: nA0 = 1; % Initial guess nA = fzero(@fn, nA0); disp(nA) function Z = fn(nA) alphaA = 0.52; T ...
7 days ago | 0
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Error: Function definition not supported in this context. Create functions in code file.
You need to turn Z=sin(2*pi*fc*p)./(pi*p); %Define truncated Sinc function% into Z=sin(2*pi*fc*p)./(pi*p); %Define trunca...
7 days ago | 1
Using a another function within ODE45
More like this (but note the comments near the end): %Default Values m_c = 2; % Container Mass s1 = 16; ...
7 days ago | 1
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Conditionals within ODE45
You could try the following simplistic approach %Default Values m_c = 2; % Container Mass s1 = 16; % Sp...
8 days ago | 1
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Need Help..............Error using stem (line 43) X must be same length as Y.
Either you want stem(t,xaa); or you want to use t1 in the definitions of xa11, xa22 etc.
8 days ago | 1
What am I doing wrong here I keep getting a plot with either to many things on it or not enough all I want is a plot with two y axis and an x axis
Like this g = 9.81; theta = 46.97; theta2= 55; v1= 13.5; v2= 16.05; x= (0:0.1:2.3); x2= (0:0.1:5.14); y= x*tan(the...
8 days ago | 0
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Two linear equation with absolute value equation
Do you mean something like this X0 = [-50 -5]; [X, Fval] = fminsearch(@(X) fn(X),X0); x2 = X(1); x1 = 50-x2; x4 = X(2); x3 =...
8 days ago | 1
10%+10%
Because the % symbol indicates that the rest of the line is a comment. So the only non comment parameter Matlab sees is the fir...
8 days ago | 1
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Function handling problem in loop
Try doc str2num to convert from text to numeric. Also, you might find it easier to define: k = [5.16 5.12 4.89 4.79 4.99 5.4...
8 days ago | 0
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I can't randomly distribute the dots
Try using Yikikz=rand(size(Elevation)).*Elevation;
8 days ago | 1
How to fix error in fsolve
Is it just a case of changing F(1) = X(1) - exp(13.5-(2700/(x(3)-55))); to F(1) = x(1) - exp(13.5-(2700/(x(3)-55)));
9 days ago | 1
Error in using Integration, How to fix it ?
Since x has t in the denominator. t=0 will cause problems, so start at t = 0.02 instead, perhaps! This would require a change i...
9 days ago | 0
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Ode and monod solver
Your equation has the following analytic solution (assuming Xa is a constant): You can plug in the known values for S0 (ie. t...
9 days ago | 1
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How to plot a large data set with markers to differentiate two overlapping lines?
How about plotting every n points. For example plot(t(1:1000:end),n_d(1:1000:end),'o') hold on plot(t(500:1000:end),n_r(500:...
11 days ago | 0
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there is also a mistake here i can't recognize it , please help
You need N = [-V3*cos(th3(ii))-40*W2(ii).^2*cos(th2(ii))+C(ii)*W3(ii).^2*cos(th3(ii))+V3*W3(ii)*sin(th3(ii)); V3*sin(t...
11 days ago | 0
How to vectorize this function?
You need a ./ (i.e. dot /) x3=@(phi) (R-((3-2.*sin(phi))./(1-0.5.*sin(phi)).*R)/4).*cos(phi) ...
11 days ago | 0
Plotting graph with Alpha and spectral radius
It works if you set i = 0.1:0.1:10. With i = 0; the inverse of S is full of Inf's.
11 days ago | 0
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Conditional with time in ode45
Include upsilon within the odefcn mu = 6.25e10^-3; eta = 6.25e10^-3; beta = 0.03813350836; gamma = 0.01165323939; delta = 1...
11 days ago | 0
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what's wrong with this code. why it show error can anyone tell?
You probably want something like this (don't enclose it with the statement 'function matlab' - that won't work). Remember to in...
11 days ago | 0
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