function f = section4(n,x0,alpha)

N = 20;
f = zeros(1,N);

for i = 1:N
    if( i == 1 )
        f(i) = 1/2*(x0+alpha/x0^(n-1));
    else
        f(i) = 1/2*(f(i-1)+alpha/f(i-1)^(n-1));
    end
end



