clear
	g = '2*t*y';
	function out = f(y,t)
	 out = evstr(g)
	endfunction

	t0 = 0.1;
        y0 = 1;
	h = 0.05;
	n = 20;
Yr =[];
Tr =[];	
        y = y0;
	t = t0;

	for j = 1:n
	k1 = f(y,t);
	k2 = f(y+   (h*k1*0.5) ,   t+(h*0.5));
        k3 = f(y+   (h*k2*0.5) ,t+(h*0.5)); 
        k4 = f(y+   (h*k3) ,       t+h);
        y = y + (h/6)*(k1 + 2*k2 + 2*k3 + k4);
	t = t+h;
	Yr(j) = y;
	Tr(j) = t;
	end
	
	R = [Tr Yr]