Alan Stevens
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Contribute at least one answer each month for 12 consecutive months
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Content Feed
Finding approximate real solution to a equation
You don't need syms here. Try the roots function. help roots
1 jour 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'...
2 jours ago | 0
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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), ...
3 jours ago | 0
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 ^
3 jours 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; ...
4 jours 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) [...
4 jours 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...
8 jours 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...
8 jours 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.
10 jours 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...
12 jours 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; %...
12 jours ago | 1
| accepted
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).
13 jours 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)...
14 jours 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);...
24 jours 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...
environ un mois 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/...
environ un mois 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 ...
environ un mois 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...
environ un mois 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
environ un mois 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...
environ un mois 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...
environ un mois 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,...
environ 2 mois ago | 1
| accepted
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...
environ 2 mois 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...
environ 2 mois ago | 0
Theta phi positive and negative conventions and conversions
Try mod(theta,180) and mod(phi,360)
environ 2 mois ago | 0
| accepted
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...
environ 2 mois ago | 0
| accepted
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.
environ 2 mois ago | 1
| accepted
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...
environ 2 mois ago | 0
| accepted
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 mois 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 mois ago | 1
