# Alan Stevens

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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 giorni ago | 0

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 giorni ago | 0

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...

10 giorni ago | 0

| accepted

calculating angle between line of best fit and x axis

Take the arctangent of the gradient of the straight line.

10 giorni ago | 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 ]; ...

11 giorni ago | 0

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) ...

11 giorni ago | 0

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) ...

12 giorni ago | 0

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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...

12 giorni ago | 0

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...

15 giorni ago | 0

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...

15 giorni ago | 0

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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...

15 giorni ago | 1

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...

16 giorni ago | 0

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...

17 giorni ago | 1

Writing the dirac function as a function handle

Try dirac_i = @(x) x==i; % This assumes i has been fixed before the function is defined

17 giorni ago | 0

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How to plot 2 graphs with input as a range and join them together?

Like this p0=0; p1=6; p2=1; p3=3; p4=3; t=[0:0.01:1]; x1 = (1/6)*[((((-t).^3)+(3*(t.^2))-(3*t)+1)*p0)+(((3*(t.^3))-(6*(t....

17 giorni ago | 0

the variable appears to change size every loop iteration

You don't need the loop: If = [0 0.5 1.0 1.5 2.0 2.5]; Ea = [0 75 150 205 242 270]; Ra = 0.14; RI = 2; la = 100; Ifield = ...

17 giorni ago | 1

Unable to find solution to matrix using Gauss Seidal code. How should I proceed to get the solution?

You are dividing by A(i,i) some of which are zero. These will introduce NaNs.

18 giorni ago | 0

Solving Eqn with Varying Variable (Ms)

Like this: a1a4 = 1./[1, 2, 4, 10]; n = 10000; p4p1 = 1:n; M = zeros(numel(a1a4),n); for j = 1:numel(a1a4) m = 1.01; ...

20 giorni ago | 1

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To solve two 2nd order coupled differential equation using ODE45?

Replace each 2nd order ODE by two 1st order ODEs. e.g. set V1 = X1', V2 = X2', then V1' = (50*sin(f(t) - V1)*V2')/sin(f(t)), V...

21 giorni ago | 0

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Using Ode45 to solve dynamics problem (ISA model)

Like this z0 = 39045; %const.h0; v0 = 0; %const.v0; t0 = 0; tf = 800; N = 60000; tspan = linspace(t0, tf, N); X ...

21 giorni ago | 0

| accepted

Curve fitting a power law function

Like this? h0=0.654; %[m] This seems to be unused h_t=[0.654;0.628;0.604;0.582;0.56;0.54;0.52;0.501;0.482;0.465;0.447;0.43;0.4...

23 giorni ago | 0

Finding approximate real solution to a equation

You don't need syms here. Try the roots function. help roots

25 giorni ago | 0

| accepted

Two Step Adam Bashford Method

As follows f=@(t,y) 3*t+y/t; alpha=5; a=1; b=2; n=3; [t, w, h] = abs2(f, a, b, alpha, n); plot(t,w,'-o'),grid xlabel('t'...

26 giorni ago | 0

| accepted

How to add iterations in Newton Raphson code of Kepler Equation

Like this M = 0.908; e = 0.725; tol = 10^-6; [E, its] = Kepler(M,e,tol); disp(['E = ' num2str(E) ' after ' num2str(its), ...

26 giorni ago | 0

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Let x=[2 4 6 8 10] and y=[1 3 5 7 9]. Compute for the vector z whose elements are equal to z= (xy+ y/x)/[(x+y)]^((y-x)) + 10^(x⁄y)

You need z = (((x.*y)+(y./x))./((x+y).^(y-x)))+10.^(x./y) % another dot here ^

26 giorni ago | 0

| accepted

how to find the root of function?

Like this? n_h0 = 0.1; %initial guess n_h = fzero(@n_h_fun, n_h0); disp(n_h) function a=n_h_fun(n_h) alpha=0.74; ...

27 giorni ago | 1

| accepted

Newton's method for 2 dimension vectors

LIke this? % Functions f = @(XY) [XY(1).^3 - 3*XY(1).*XY(2).^2 - 1; 3*XY(1).^2.*XY(2) - XY(2).^3]; J = @(XY) [...

28 giorni ago | 0

How to plot a (which is changing from 0-1 in 0.01 increments) vs x(2) (using a for loop and fsolve to find the solution of a nonlinear equation containing x(s) sol based on a

Your first equation is a simple quadratic in x(1); your second is a quadratic in x(2) that depends on x(1), so, assuming you are...

circa un mese ago | 0

to plot alpha(a) vs diameter(D) in the given problem. where A = l*sin(b), B = l*cos(b), C = ( h + 0.5*D )*sin(b) − 0.5*D*tan(b) and E = ( h + 0.5*D)*cos(b) − 0.5*D.

Try replacing D within the j-loop by D(j). Also add something like alpha(j) = a after the end of the i-loop (but inside the j-l...

circa un mese ago | 0