Insufficient input arguments. continues to come out. Help

2.187

%This progrem will use dfuncl.m

tspan = 0: 0.05: 8;

y = [0.4; 0;0];

[t , y]= ode23(odefun, tspan, y);

plot (t, y(:, 1));

xlabel ('t');

ylabel ('y(1');

title ('problem 2.187');

function f = odefun( ~ , y )

u = 0.5;

k = 100;

m = 5;

f=zeros(2,1);

f(1) = y(2);

f(2) = -u*9.81*sign(y(2))-k*y(1)/m;

end

-------------------------------------------------------------------

>> pr187

Insufficient input arguments.

an error occurred : pr187>odefun (16. line)

f(1) = y(2);

an error occurred: pr187 (5. line )

[t , y]= ode23(odefun, tspan, y);

Answer 1

[Voss]

Try changing this:

[t , y]= ode23(odefun, tspan, y);

to this:

[t , y]= ode23(@odefun, tspan, y);