Community Profile # Alan Stevens

Last seen: 1 giorno ago Active since 2020

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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...

1 giorno 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...

2 giorni ago | 0

Solving factorial equation with integer variables: Empty sym 0-by-1
Set x-2 = 659 and y-x = 679 for one solution, and x-2 = 679 and y-x = 659 for another.

3 giorni ago | 0

Unable to plot exponential graphs properly
One possibility t = linspace(-10,10,400); y1 = exp(t); y2 = exp(-t); y3 = exp(2*t); plot(t,y1,t,y2,t,y3) legend('y1','y2...

5 giorni ago | 0

Not enough input arguments.
Like this?: global PT S DELH Q CPA CPB CPC CPD NA NC NB ND NE NT PT = 1.5; % PT is total pressure in atmospheres S = 0.05; %...

5 giorni ago | 1

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speed up integrating the same function over many overlapping intervals?
How about using cumtrapz to do the cumulative integral from 0 to max(X) just once, then select the sections specified by X(i).

7 giorni ago | 0

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Solving single variable equation where other variables depends on that single variable
Try using fzero. For example: f = @(x) x.^2 +1./x; % arbitrary function: replace with your own y = @(x) f(x); z = @(x)...

7 giorni ago | 0

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last value of array
Do you mean something like this %plot n vs x n vs y for n=1:10 [t,r]=ode45(@fn,[0 14],[0.01+n 0.01 ]); xlast(n) = r(end,1);...

17 giorni ago | 0

How to keep both readability and calculation speed when using anonymous functions?
How about something like hexp = @(x,y) exp(1i*(x+y)); x = ..; % set to whatever is required y = sqrt(x.^2 + A^2); h1 = h...

27 giorni ago | 0

Non-linear system of inequalities
First plot some lines that bound the inequalities % G>21 % 15<=S<=18 % 61<=2S+G<=63 % 30<=atan(S/G)<=45 -> sqrt(3)/3 <= S/...

27 giorni ago | 1

How to request a specific user input?
You don't need "input" twice: prompt = 'Please enter 1 for EXP1 and 2 for EXP2:'; % ask EXP = input(prompt); if ...

28 giorni ago | 0

Same time steps for ODE function and OutputFcn
You could simply calculate k = x.^2 + y.^2; immediately after [x,y] = ode45(@myode,tspan,1,options); However, have you real...

29 giorni ago | 0

Please how do I show multiple custom equations fittings for a data set on the same Graph/Figure?
Use the "hold on" command after the first plot. help hold

circa un mese ago | 0

Error in multipying a 3 by 3 matrix with a 3 by 1
Check that the number of columns in the first matrix matches the number of rows in the second matrix. Ri has 3 columns, C has 3...

circa un mese ago | 0

Any mathematical mistake in my script ?
Easier to check like this b=1; t=1; br=1; Pr=1; d = @(n) (2*n + 1)*pi; c = @(n) d(n).^2; k1 = @(n) ( 1 - exp( -c(n)*t/(4...

circa un mese ago | 0

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How to solve a 2nd-order ODE system with space-dependent variable with ODE45?
More like this perhaps dY = [0, 0.0026, 0.0082, 0.0138, 0.0194, 0.0250, 0.0306, 0.0362, 0.0418, 0.0475, 0.0532, 0.0589, 0.0647,...

circa un mese ago | 1

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Trapezoidal integration for pressure
Do you mean something like this? x = [0.025 0.0233 0.0243 0.02477 0.0254]; z = [0.3658 0.3722 0.3991 0.433 0.477]; P = [24...

circa un mese ago | 0

How to solve this 4th order linear ODE with ode45?
You need to define tspan x_1_0 = [2; 1/2; 0; 0]; tspan = [0 10]; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% [t_1,x_1] = ode45(@f, tsp...

circa un mese ago | 0

Theta phi positive and negative conventions and conversions
Try mod(theta,180) and mod(phi,360)

circa 2 mesi ago | 0

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I'm trying to solve Bernoulli equation in differential form.
If p is constant then dp/dx = 0, hence du/dx = 0, which means u is constant. If you meant the pressure gradient is constant the...

circa 2 mesi ago | 0

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How to use figure out steady state during ODE
Try ix = find(Y(:,1)==max(Y(:,1)),1) disp(T(ix)) after your plot command.

circa 2 mesi ago | 1

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Runge-Kutta integration of the Taylor-Maccoll eq
Shouldn't k1 = h*F1(t, y1(i), y2(i)); m1 = h*F1(t, y1(i), y2(i)); k2 = h*F2(t+0.5*h, y1(i)+0.5*h, y2(i...

circa 2 mesi ago | 0

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How can I shade the area between a curve and a vertical line?
Try help fill or help patch Although they refer to polygons, you could easily represent your curve as a multi-segment polyg...

2 mesi ago | 0

Finding best parametric function estimation for ODE of first order
First plot the points, ui vs xi to see what sort of curve it might be. If it looks like it could be a polynomial (as in the cas...

2 mesi ago | 1

Impose a numerical limit on the value of a sum of two vectors
One possibility is min(max(a1),a1+a2)

2 mesi ago | 1

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How read Matrix Market data into MATLAB?
Do you mean like this: %%MatrixMarket matrix coordinate real symmetric % System: M x_dotdot + E x_dot + K x = B u % y...

2 mesi ago | 0

rounding the imaginary part of the number
Z = 0.0000e+00 + 7.8765e-04*1i; format shortG round(Z,4)

2 mesi ago | 1

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How can I model second order ODE with matrices and external forcing?
Like this perhaps (I've made up arbitrary data; you will obviously have to replace it with your own) x0 = [1; -1]; v0 = [0; 0]...

2 mesi ago | 0