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...

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...

7 meses 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...

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...

7 meses ago | 0

Answered

Break the for loop

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

Break the for loop

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

7 meses ago | 0

Answered

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*(...

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*(...

7 meses 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...

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...

7 meses 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); ...

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); ...

7 meses 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 ...

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 ...

7 meses ago | 1

Answered

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,...

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,...

7 meses 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 .*

Problem with fplot function - displays grey zone instead of functions

Change all the ^ to .^ (i.e. dot^)and the * to .*

7 meses ago | 1

Answered

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...

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...

7 meses ago | 0

Answered

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)...

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)...

7 meses ago | 0

Answered

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...

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...

7 meses 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...

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...

7 meses 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;...

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;...

7 meses 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...

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...

7 meses 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 ...

Simplify Matrix decimal to integers

One way is M = [881/2158 985/1393 780/1351 881/2158 -985/1393 780/1351 -881/1079 ...

7 meses ago | 0

Answered

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...

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...

7 meses 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 ...

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 ...

8 meses ago | 0

Answered

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...

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...

8 meses ago | 0

Answered

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...

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...

8 meses 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.

calculating angle between line of best fit and x axis

Take the arctangent of the gradient of the straight line.

8 meses ago | 0

Answered

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 ]; ...

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 ]; ...

8 meses ago | 0

Answered

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) ...

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) ...

8 meses 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) ...

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) ...

8 meses 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...

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...

8 meses 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...

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...

8 meses ago | 0

Answered

Solving a first order ODE with Euler backwards method

Your y_true is only valid for t>= 5 (smaller values give imaginary results for y). So, try going from 5 to 8: % y_true = log(t...

Solving a first order ODE with Euler backwards method

Your y_true is only valid for t>= 5 (smaller values give imaginary results for y). So, try going from 5 to 8: % y_true = log(t...

8 meses ago | 0

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Answered

Need help to create a loop

How about: e=2.7183; gamma=0.1333; k = [1,9,23,7,23,9,20,29,63,102,73,59,27,130,75,185,70,92,326]; Rt=0:0.01:10; P = zero...

Need help to create a loop

How about: e=2.7183; gamma=0.1333; k = [1,9,23,7,23,9,20,29,63,102,73,59,27,130,75,185,70,92,326]; Rt=0:0.01:10; P = zero...

8 meses ago | 1

Answered

Newton's method iterations

I suggest you plot a graph of your function, then you can see where good initial estimates would be. For example f = @(x) 2*ex...

Newton's method iterations

I suggest you plot a graph of your function, then you can see where good initial estimates would be. For example f = @(x) 2*ex...

8 meses ago | 0

Answered

the variable appears to change size every loop iteration

Answered here: https://uk.mathworks.com/matlabcentral/answers/1464024-the-variable-appears-to-change-size-every-loop-iteration?s...

the variable appears to change size every loop iteration

Answered here: https://uk.mathworks.com/matlabcentral/answers/1464024-the-variable-appears-to-change-size-every-loop-iteration?s...

8 meses ago | 1