I try to plot the solution of a system of ODE, on [-10,10], for the initial data [0.001 0.001], using the function:
function dwdt=systode(t,w)
if 0< t<1
f = t*(3-2*t);
if -1<t< 0
f=t*(3+2*t);
else
f = 1/t;
end;
if 0< t <1
h=4*t^4-12*t^3+9*t^2-4*t+3;
if -1< t < 0
h=4*t^4+12*t^3+9*t^2+4*t+3;
else
h=0;
end;
beta=0.5+exp(-abs(t));
dwdt=zeros(2,1);
dwdt(1)=-f*w(1)+w(2);
dwdt(2)=-beta*w(1)-f*w(2)+h*w(1)-f*w(1)^2;
end
The coefficients f(t) and g(t) are piecewise functions as follows.

With the commands
tspan = [-10 10];
z0=[0.001 0.001];
[t,z] = ode45(@(t,z) systode(t,z), tspan, z0);
figure
plot(t,z(:,1),’r’);
I get the message
tspan = [-10 10];
↑
Error: Invalid use of operator.
Where could be the mistake? I am also not sure that I defined correctly the functions f, h, .I try to plot the solution of a system of ODE, on [-10,10], for the initial data [0.001 0.001], using the function:
function dwdt=systode(t,w)
if 0< t<1
f = t*(3-2*t);
if -1<t< 0
f=t*(3+2*t);
else
f = 1/t;
end;
if 0< t <1
h=4*t^4-12*t^3+9*t^2-4*t+3;
if -1< t < 0
h=4*t^4+12*t^3+9*t^2+4*t+3;
else
h=0;
end;
beta=0.5+exp(-abs(t));
dwdt=zeros(2,1);
dwdt(1)=-f*w(1)+w(2);
dwdt(2)=-beta*w(1)-f*w(2)+h*w(1)-f*w(1)^2;
end
The coefficients f(t) and g(t) are piecewise functions as follows.

With the commands
tspan = [-10 10];
z0=[0.001 0.001];
[t,z] = ode45(@(t,z) systode(t,z), tspan, z0);
figure
plot(t,z(:,1),’r’);
I get the message
tspan = [-10 10];
↑
Error: Invalid use of operator.
Where could be the mistake? I am also not sure that I defined correctly the functions f, h, . I try to plot the solution of a system of ODE, on [-10,10], for the initial data [0.001 0.001], using the function:
function dwdt=systode(t,w)
if 0< t<1
f = t*(3-2*t);
if -1<t< 0
f=t*(3+2*t);
else
f = 1/t;
end;
if 0< t <1
h=4*t^4-12*t^3+9*t^2-4*t+3;
if -1< t < 0
h=4*t^4+12*t^3+9*t^2+4*t+3;
else
h=0;
end;
beta=0.5+exp(-abs(t));
dwdt=zeros(2,1);
dwdt(1)=-f*w(1)+w(2);
dwdt(2)=-beta*w(1)-f*w(2)+h*w(1)-f*w(1)^2;
end
The coefficients f(t) and g(t) are piecewise functions as follows.

With the commands
tspan = [-10 10];
z0=[0.001 0.001];
[t,z] = ode45(@(t,z) systode(t,z), tspan, z0);
figure
plot(t,z(:,1),’r’);
I get the message
tspan = [-10 10];
↑
Error: Invalid use of operator.
Where could be the mistake? I am also not sure that I defined correctly the functions f, h, . ode45 MATLAB Answers — New Questions

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