Alan Stevens

Last seen: Today | Active since 2020

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Answered
Solve a system of 3 second order equations
Write your equations as 6 first order equations like so: where I've assumed you have pre-defined omegaout and thetaout as fun...

11 hours ago | 0

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Unable to solve nonlinear equation using fsolve as the message shows No solution found
fminsearch makes a reasonable attempt: F1 = @(a,b) -9.135789053E+00-log(a)+166.2509975*a+5.84074229*b+... -166.2509975*a^2...

1 day ago | 2

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How to solve and plot this set of differential equations?
If rho starts at 0, then drho/dtheta will be zero and rho will not change from zero according to your first ode. If rho and drh...

3 days ago | 0

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How can I add two differential equations to the system in a given time interval?
Like this? (though I'm not sure I've interpreted which constants apply during which interval correctly!) Tspan = 0:30; C0 =...

7 days ago | 1

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How do I plot Rosette-like diagram in this case?
Something like this? data=[10 10 30 100; 20 50 70 150; 30 45 60 120]; theta0 = deg2rad(data(:,2)); thetaf = deg2r...

8 days ago | 1

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Iteration of multiple nonlinear functions
Here's a quick and dirty way. I'll leave you to modify the following to record all the temperatures at every step. %Given valu...

19 days ago | 0

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converting table values to RPM
B{:,7}./(2*pi)*60

21 days ago | 0

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using num2str for subplot titles
Try title(['Q1S', num2str(k)]) i.e. enclose the two terms within square brackets.

21 days ago | 0

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control and simulation of petroleum distillation column
The following works, but probably doesn't contain all the right data or equations! % CALCULATE MATERIAL BALANCES FOR THE DISTIL...

22 days ago | 0

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Error with plot command
You haven't specified function atten_func_dist, so we can't run your code to test it. You specify fre as a constant, then us...

23 days ago | 2

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How to combine multiple curve fits in one plot
Use hold on after plotting the first figure

25 days ago | 0

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How to represent [airfoil] coordinates as a polynomial
How about using a spline fit? After loading your data and calling the first column x and the second column y try xfit = linspa...

27 days ago | 0

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1D melting problem with Neumann's analytical solution
eps is a built-in constant so better not to use it as a variable. Your png files show it is xi not epsilon. Try the following ...

27 days ago | 0

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Overlay plots of different angles of incidence.
Remove the word figure and add hold on after the plot grid on [Fr,In] = meshgrid(Frequency,Incident); plot3(Fr,In,Reflectivit...

28 days ago | 0

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How can write in MATLAB the following expression?
Try ket0 = [1; 0; 0] ket1 = [0; 1; 0]

1 month ago | 0

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I don't understand why does it give error?
Put the functions at the end. Tidy up one or two minor errors to get: %########### BF-PSO.m file ############# %####### Butter...

1 month ago | 0

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How to count steps represented by the acceleration data given in text file?
Like this (you can plot the other two - look up help on subplot): M = csvread('walking.txt'); x = M(:,1); y = M(:,2); z = M(:,...

1 month ago | 0

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Answered
Bisection method add iteration table into my code
Something like this? my_fun = @(x) exp(x) - 3*x; low = 0; high = 1; tolerance = .00001; [x, x0] = bisection(my_fun, low, hi...

1 month ago | 0

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I'm trying to solve this code for internal ballistic using ode45.This is my first time using ode
This works (note that Matlab doesn't accept implied multiplication), but doesn't look sensible - what about deriv(2)? y_initial...

2 months ago | 0

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Answered
Error with brackets symsum
Do you mean something more like this? N = 100; % Total number of particles one = 1; alpha = 1; K = 7; % 7 states n0 = 4*o...

2 months ago | 0

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How to plot the figure in LT?
Use the mod function help mod

2 months ago | 0

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How to deal with rounding error in this example?
How about i = 1:20001; A = -2000 + (i-1)*0.2;

2 months ago | 1

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Get back variables out of function inside a for loop
Here's one way J = [2.5 27 56]; WZ = [12.2 23.2 33]; M1 = 22; I1 = 2600; for ii = 1:numel(WZ) slope(ii) = (J(ii)-M1)...

2 months ago | 1

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Plot dispersion curves using Bloch theorem
Like this? OmegaR = 1; mR = 0.125; Omega = 0:0.01:2.5; mu = acos(1 - Omega.^2.*(1+mR./(1-Omega.^2/OmegaR^2))/2); plot(i...

2 months ago | 0

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Answered
how to do sensitivity analysis of three variables using MATLAB
Depends what your measure of sensitivity is. One possibility is to do a Monte-Carlo simulation and use the standard error on th...

2 months ago | 0

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MATLAB doesn't plot my function
Try fplot(test1)

2 months ago | 0

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I am trying to plot the each value of C at different theta values, but I found an error. Error: Invalid expression. When calling a function or indexing a variable, use parenth
Do you want something more along the following lines? c=[0.5,0.75,1,1.1]; theta=-pi:0.01:pi; %a=zeros(1,629); for k=1:numel(...

2 months ago | 0

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Trying to make euler's method program work
Like this: % Arbitrary values here - insert your own x0 = 0; x_end = 10; h = 0.1; y0 = 1; n = fix((x_end-x0)/h)+1; ...

2 months ago | 0

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Getting inaccurate eigenvalue with eig command. Please suggest me some other command or small series of steps to find accurate eigen value for Generalized Eigenvalue Problem.
Like this: A =[ -11.0913 0 0 0 0 0 0 0 0 0 0 ...

2 months ago | 0

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Answered
Why does integration of an exponential function generate noisy results as opposed to its analytical solution?
You have a singularity when t = x(ii). Here's a rough and ready way to do the numerical integral (hmm! not sure the result is c...

2 months ago | 0

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