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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...

3 months ago | 1

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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...

3 months ago | 1

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Answered
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); ...

3 months ago | 1

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Answered
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)

3 months ago | 0

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Answered
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...

3 months ago | 0

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Answered
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...

3 months ago | 0

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Break the for loop
Something like this perhaps: fib = [1; 1]; its = 0; keepgoing = true; while keepgoing its = its+1; r = rand; ...

3 months ago | 0

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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*(...

3 months ago | 0

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Answered
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...

3 months ago | 0

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Answered
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); ...

3 months ago | 0

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Answered
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 ...

3 months ago | 1

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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,...

3 months ago | 1

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Answered
Problem with fplot function - displays grey zone instead of functions
Change all the ^ to .^ (i.e. dot^)and the * to .*

3 months ago | 1

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I would like to create a handle function by for loop in matlab, but it does not work. I will be thankful if some body help me.
More like this? sfn = @(x,a,b) (a - b)*x; a=[1 2 3]; b=[4 5 6]; n=length(a); x = 1; % specify whatever x value you want f...

3 months ago | 0

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How to solve this implicit equation in matlab?
Good idea to plot a graph first, to see roughly where the root lies. Then use fzero. For example:: fn = @(x)log((0.77*x-0.77)...

3 months ago | 0

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Problem with solving discrete element method using leap frog method
The following gets the code working, but I've no idea if the results are meaningful!! n_part=4; kn=5; kt=2/7*kn; m=0.3; g=9...

3 months ago | 0

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Answered
Write a loop to plot a model graph
A little more like this. You need a smaller value of dv and a while loop. The fit isn't very good! %% Observed Wave dispersi...

3 months ago | 0

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Answered
Making a line thought points plotted from for loop in MATLAB
Like this? R1= 1399.580e+6; C1= 374.868e-6; R2= 1497.005e+6; C2= 350.472e-6; R3= 19573.407e+6; C3= 2429.373e-12;...

3 months ago | 0

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Answered
How do I plot and return the values of multiple intersections between a function and zero?
Here's one possibility (though you get repeated results for the roots!): det_a = @(x) sin(x).*cosh(x) - cos(x).*sinh(x); x=0:1...

3 months ago | 0

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Answered
Simplify Matrix decimal to integers
One way is M = [881/2158 985/1393 780/1351 881/2158 -985/1393 780/1351 -881/1079 ...

3 months ago | 0

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Tring to solve for a transcendental equation
You can rearrange the equation as eigen*tan(eigen) = Bi and use fzero as below. However, because of the nature of tan, your res...

3 months ago | 0

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Answered
Question regarding MATLAB code to solve for electron in constant electric and magnetic field
If you are going to use global variables they need to be declared outside the function as well as inside. Your values of q and ...

3 months ago | 0

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Hello, I am trying to plot the transmission coefficient vs energy for the double barrier potential, but I get an error. May I know what I have done wrong here?
See the following V_0 = 0.2800; % Barrier strength in eV hbar = 1.054571596e-34; % Reduced Planck constant m = 5.465629128e-3...

3 months ago | 0

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Simulation of point kinetics reactor equations
There are seven equations if you are using all six delayed neutron groups. You don't give your reactivity, nor the individual b...

3 months ago | 1

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Answered
calculating angle between line of best fit and x axis
Take the arctangent of the gradient of the straight line.

3 months ago | 0

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deleting separate zeros from vector
Here's one way (there is probably a slicker way!): A = [ 0 0 1 0 0 0 1 0 1 0 0 1 5 9 8 2 0 3 0 1 0 0 0 ]; ...

4 months ago | 0

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Making a Euler Method script to solve for velocity but am encountering "Array indices must be positive integers or logical values" Error
Try changing your loop to for i=1:numel(t) %%% i loop not t f = (g - (D * p * A * v(i).^2)/(2*m)); %%% v(i) v(i+1) ...

4 months ago | 0

Answered
Error solving for a particular variable from two equations
You could use fzero: TonTc = 0.01:0.01:0.99; a = zeros(1,numel(TonTc)); a0 = 1; % initial giuess for k = 1:numel(a) ...

4 months ago | 0

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Answered
Replacing sym with function handle
Do you mean something like this? phi = pi/3; [nr, wr] = fn(phi); disp(phi) disp(nr(4)+56*3/2) disp(wr(4)) function [nr...

4 months ago | 0

Answered
I'm trying to solve this system of ODE's describing a mechanical spring model.
Might be better to forget about symbolics, treat each 2nd order ode as two first order ode's and do the following: %applied for...

4 months ago | 0

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