Alan Stevens
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Contribute at least one answer each month for 12 consecutive months
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Hi, what does ; exactly mean?
It means start a new row, e.g. x = [1 2; 3 4]; disp(x)
1 giorno ago | 0
Solve the IVP y′′′=sin(y2)+y′+cos(t), provided with an appropriate set of initial conditions of your choice, and using Matlab's ODE45 function.
Like this? (Note the IC for d^2y/dt^2 must be consistent with the values chosen for y(0) and dy(0)/dt). Change the IC's and tim...
11 giorni ago | 0
Need Help Solving System of ODEs
You haven't included the first term on the right-hand side of your equation for dV/dt, nor for dgamma/dt.
12 giorni ago | 1
spring mass using ode45
Like this x0 = [0; 0]; tspan = [0, 10]; [t, x] = ode45(@func, tspan, x0); subplot(2,1,1) plot(t, x(:, 1)); grid('on...
12 giorni ago | 0
I am getting error in this program. Please suggest the corrections.
Change c = [1 2 2 3 4 5 6 7]; to c = [1 2 3 4 5 6 7];
13 giorni ago | 1
Hello, I'm trying to plot one non-piecewise function and two piecewise functions in one graph but I keep getting an error. I don't understand the two error messages below.
You need to put the non-local functions at the end, as in the following. There were several other errors. I don't know if my co...
13 giorni ago | 0
How to Solve equation using Eulers method in Matlab?
Here's part (a) for you - definitely not a straight line!
16 giorni ago | 0
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I need to set up a Runge Kutta solver for water leaving a bucket through a certain diameter nozzle as function of time, it says array indices must be positive integers/log val
Indices in Matlab start at 1, not 0, so you need for i=1:60:200 not for i=0:60:200
18 giorni ago | 0
How to get one output for each input into an equation in MATLAB?
mu = mu_max * (x./(x+Ks)); % Notice it is ./ not just /
21 giorni ago | 0
How to solve 'Index number exceeds number of array elements(1)'
You don't update XSOL, so when ct is 2, XSOL(ct) doesn't exist.
21 giorni ago | 0
A question about FitzHugh-Nagumo model
Like this? tspan = [0 100]; v0 = 0; w0 = 0; IC = [v0 w0]; A=0.5; B=0.05; Epsilon=0.005; I=@(t)sin(t); %%%%%%%%%%%%%%...
21 giorni ago | 0
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How to find parameters that minimize a difference
Use fminsearch and use the norm of the differences. help fminsearch
22 giorni ago | 2
I want to combine 2 variables in matlab into one variable
If they are imported as, say, c1 and c2, then you can simply write c = [c1; c2]; then delete the c1 and c2 if you don't need t...
23 giorni ago | 0
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How can i call an equation and it's derivative inside a matlab function?
Like this, perhaps: % TC is given in terms of percentage! x0=0; TC=10^-4; error=TC+1; i=0; x(1)=x0; while(error>TC) [f...
23 giorni ago | 0
simple Fixed Point Iteration
Probably more like this (though you don't seem to have used function f anywhere): n = 11; x = zeros(1,numel(n)); ea = zeros(1...
23 giorni ago | 0
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I want Estimate log to the base 10 value using 'x' number such that 10^estimated value is equal to or just exceeding x.
< not <= a = log10_bywhile( 50, 0.1 ) b = log10_bywhile( 100, 1 ) function [out] = log10_bywhile(x, inc) esmt = 0; % if...
26 giorni ago | 0
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How can I change the value of Y in the columns whare the value of X is zero in matrix ?
Like this XY = [1 5 0 10 3 26 0 5]; XY(XY(:,1)==0,2) = 1.5
26 giorni ago | 1
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multiple equations multiple variables solve command does not work
These equations are linear in the unknowns, so can be solved as follows: % M*X = V where X = [b; d; e] % and the coefficien...
28 giorni ago | 1
Is there an error in the if else statement?
Yes, among others! See: L1 = 16.87; %cm L2 = 60.35; L3 = 16.81; L4 = 63.06; L5 = 42.62; L7 = 19.64; theta_1 = 105.47; %de...
29 giorni ago | 1
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Solving ODE Boundary Value Problem by Finite Difference Method
I think you just need to change b(i+1) = (w*xi(L-xi))/(2*E*I); to b(i+1) = (w*xi*(L-xi))/(2*E*I); ...
circa un mese ago | 1
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Computing the double integral of a surface
Like this syms x y z = @(x,y) x.^2 + y.^2; surface_int = integral2(z,1,2,4,9); disp(surface_int)
circa un mese ago | 0
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Mod Euler Method with two ODEs
Like this %Mod_Euler_method Modified Euler's method % [t, w, h] = euler_method(f, a, b, alpha, n) performs Modified Euler's me...
circa un mese ago | 0
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im having trouble finding the right values for this codes
This should allow you to find the right values, though it might not be quite the way you were tasked to do it! %Initial Conditi...
circa un mese ago | 0
Break the for loop
Something like this perhaps: fib = [1; 1]; its = 0; keepgoing = true; while keepgoing its = its+1; r = rand; ...
circa un mese ago | 0
How to take data on a column matrix (2661 x 1 double) for every 4 row then 3, sequently? So we take data only row 1, 5, 8, 12, 15, 19, 22, ... etc? Thank you.
Here's one way. There's probably a neater way. data=rand(1,2661); n = ceil(2661/3.5); ptr(1)=1; for i = 2:n ptr(i) = 4*(...
circa un mese ago | 0
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Random draws from conditional multinomial distribution
Something like u = rand(1) if u<0.2 d = 0; elseif u<0.7 d = 2571; elseif u<0.9 d = 2571^2; else d = 25...
circa un mese ago | 0
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How to define and plot a function with input range?
Like so: pt = @(t) (1 ./ (1 + t .^ 2)).*(t>=-0.5).*(t<=0.5); x = 0:0.01:10; y = 2*pt(x-1) + 4*pt(x-2) + 3*pt(x-3) + pt(x-4); ...
circa un mese ago | 0
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Plot the slope of a parabola with only the data points being known
Like this? x = linspace(-0.5,0.5,25); %length in (meters) def_3mm_no_grav = -[0.00 5.82e-1 1.08 1.53 1.94 2.30 2.62 2.89 3.12 ...
circa un mese ago | 1
SIRE with vaccine model
Like this tspan = [0 1.5]; options = odeset('Refine', 10, 'RelTol', 1e-4); y0 = [5185000*0.3 5185000*0.7 1 1 0 0 0 0]; [t,...
circa un mese ago | 1
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