function yy = rk4(t0,y0,ts,n)

t = t0;
y = y0;
tstop = ts;
tsteps = n;

h = (tstop-t) / tsteps;

for i = 1 : tsteps
    t(i+1) = t(i) + h;
    f1 = func8(t(i), y(i));
    f2 = func8(t(i)+h/2, y(i)+h*f1/2);
    f3 = func8(t(i)+h/2, y(i)+h*f2/2);
    f4 = func8(t(i+1), y(i)+h*f3);
    y(i+1) = y(i) + h/6*(f1+2*f2+2*f3+f4);
end

yy = y;