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MATLAB program:
x y z b c is x(1——5), Y isn’t in the programODE45_fun【m.file】:
function dx=ODE45_fun(t,x)
dx = zeros(5,1); % a column vector
a1=1;a2=1;e1=9;e2=7;f1=56;f2=98;g1=76;g2=665;
a=a1+a2; e=e1+e2; f=f1+f2; g=g1+g2;
dx(1)=x(3)-x(2)+x(4)*x(2)-2*x(5)*x(2)-x(2)*x(2)-x(5)-e-f-g;
dx(2)=x(1)-x(3)+x(4)*x(2)-x(2)*x(2)-x(5)*x(5)-x(5)*x(2)-e*f-g;
dx(3)=x(2)-x(1)+x(5)*x(1)-x(4)*x(3)+x(3)+x(4)+e*g+f;
dx(4)=x(5)*a+x(3)*x(1)+x(3)+e*f*g*(x(4)*x(5)+x(2)*x(3)+e*f+e*g)
dx(5)=x(4)*a+x(2)*x(1)-e*f*x(1)-x(2)*x(2)*x(5)-x(2)*x(5)*x(5)-e*f-f*g
dx=[dx(1);dx(2);dx(3);dx(4);dx(5)]; %dx=[dx(1);dx(2);dx(3);dx(4);dx(5);dx(6)];
ODE45_main【m.file】:
tspan=[0,1e-5];
x0=[0;0.1;2;0;0.1];
[t,x]=ode45('ODE45_fun',tspan,x0);
data=[t,x];
save ODE45_data.txt data -ascii
subplot(2,3,1),plot(t,x(1))
subplot(2,3,2),plot(t,x(2))
subplot(2,3,3),plot(t,x(3))
subplot(2,3,4),plot(t,x(4))
subplot(2,3,5),plot(t,x(5))
%subplot(2,3,6),plot(t,x(6))
This program is in fact correct
【questions】 (1)Y=x(4)*x(5)+x(2)*x(3)+e*f+e*g
How can I calculate Y with the program(ODE45_main and ODE45_fun)?
(2)tspan=[0,1e-5];
How long it would take for calculation?
Best Answer