Hi Friends

I want to plot variables (b,u) that are in function "step" .

function main

[t,v]=ode45('step',[0 20],0,[]);

plot(t,v)

function dv=step(t,v)

c1=1;

if t<10

u=1;

else

u=-1;

end

dv=c1*u-2*v;

b=dv/2;

but these variables are unknown in function "main".

thanks.