Matlab second order derivative

Question

I have followed the tutorial on http://www.mit.edu/people/abbe/matlab/ode.html and prepared a function as follows:

function dxy = diffxy(xy)
%
%split xy into variables in our equations
%
x = xy(1);
xdot = xy(2);
y = xy(3);
%
% define the derivatives of these variables from equations
%
xdot = xdot;
ydot = 3*x + 2*y + 5;
xdoubledot = 3 - ydot + 2*xdot;
%
%return the derivatives in dxy in the right order
%
dxy = [xdot; xdoubledot; ydot]
end

When I call it using

[T, XY] = ode45('diffxy',0,10,[0 1 0])

I get an error

??? Error using ==> diffxy
Too many input arguments.

I also tried

XY= ode45(@diffxy,[0 10],[0;1;0])

Anybody have any idea?

Answer 1

haven't read the whole tutorial but aren't you supposed to define your function as

function dxy = diffxy(t, xy)

where t is time vector