% Euler's method for an IVP
%
function [x, y] = Euler(f, tspan, y0, n)
%
% The procedure solves d.e. y' = f(x,y) with initial 
% condition y(a) = y0 using n steps of Euler's method.
%
% Step size: h = (b-a)/n
%
a = tspan(1); b = tspan(2); h = (b-a)/n;
x = (a+h : h : b);
y(1) = y0 + h*feval(f, a, y0);
%
for i = 2 : n
    y(i) = y(i-1) + h*feval(f, x(i-1), y(i-1));
end
%
x = [a x];
y = [y0 y];