I'm having trouble with the differential equation example:

I have input the following into MatLab--

van der Pol example:

function dydt = vdp1(t,y)
dydt = [y(2); (1-y(1)^2*y(2)-y(1)]; 
[t,y] = ode45(@vdp1, [0 20], [2; 0]);
plot(t,y(:,t), '-',t,y(:,2),'--')

When I try to run this as a program, it returns the error message 'not enough input arguments'.

I tried another example for a 1st order differential equation:

function dydt = lineary1(t,y)
dydt = [y(1)];
[t,y] = ode45(@lineary1, [0 5], [0]);
plot(t,y)

When I ran that program, I saw the same error message.

What am I doing wrong?

Answer 1

[madhan ravi]

function dydt = lineary1(t,y) % should be saved as lineary1.m
dydt = y(1);

And in another file named "Experiment.m"

[t,y] = ode45(@lineary1, [0 5], [0]);
plot(t,y)