function [t,y] = euler_tdelillo2(f,tspan,y0,n)
% euler
t0=tspan(1);
tf=tspan(2);
h=(tf-t0)/n;
y(1,:)=y0;
t(1,1)=t0;
for k=1:n
  y(k+1,:) = y(k,:)+ h*f(t(k,1),y(k,:));
  t(k+1,1) = t(k,1) + h;
end

