Solve system of differential equations

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Yokuna
Yokuna el 16 de Mayo de 2022
Comentada: Torsten el 16 de Mayo de 2022
I am facing problem in solving the differential equation
is a vector () as shown in code and is also a vector (). x11=[x1,y1]. I want to solve , where represents derivative with respect to time. Can any one help me to find out x11 vs time. (Note and x11 are the same.) (Preferably use fsolve as I tried using it).
close all
clear all
clc
x01=-5;y01=-7;
x0=[x01,y01]';
beta=25;
syms x1 y1 t
x11=[x1,y1]';
c1=(1/2)*(x1-i*sin(t))^2+(3/2)*(y1-i*cos(t))^2;
row=100*exp(0.1*t);
g1=y1-x1-cos(t);
L1=c1-(1/row)*log(1-row*g1);
grad1 = gradient(L1,x11');
hess1 = hessian(L1,x11');
phi1=-(hess1)^(-1)*(grad1+diff(grad1,t));
u1=-beta*(hess1)^(-1)*x11+phi1
u1 = 
  2 comentarios
Torsten
Torsten el 16 de Mayo de 2022
u1 is a 2x2 matrix, x11 is a 2x1 vector.
What do you mean by
x11dot = u1
?
Maybe you mean
x11dot = u1*x1
?
Yokuna
Yokuna el 16 de Mayo de 2022
Thanks for pointing out, I have corrected the question.

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Respuesta aceptada

Torsten
Torsten el 16 de Mayo de 2022
x01=-5;y01=-7;
x0=[x01,y01]';
beta=25;
syms x1 y1 t
x11=[x1,y1]';
c1=(1/2)*(x1-i*sin(t))^2+(3/2)*(y1-i*cos(t))^2;
row=100*exp(0.1*t);
g1=y1-x1-cos(t);
L1=c1-(1/row)*log(1-row*g1);
grad1 = gradient(L1,x11');
hess1 = hessian(L1,x11');
phi1=-(hess1)^(-1)*(grad1+diff(grad1,t));
u1=-beta*(hess1)^(-1)*x11+phi1
fun = matlabFunction(u1,'Vars',{t,x1,y1})
fun = @(t,y)fun(t,x1,y1);
y0 = [x01,y01];
tspan = [0 1]
[T,Y] = ode45(fun,tspan,y0)
plot(T,[real(Y),imag(Y)])
  2 comentarios
Yokuna
Yokuna el 16 de Mayo de 2022
It gives error solving it through ode45, as the inputs needs to be floats.
Torsten
Torsten el 16 de Mayo de 2022
Replace
fun = @(t,y)fun(t,x1,y1);
by
fun = @(t,y)fun(t,y(1),y(2));

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