k=[1:5]
N=5;
xk=cos(2*pi*k/N);
dk=2*sin(2*pi*k/N);
xk1=cos(2*pi*(k-1)/N);
R=[mean(xk*xk'),mean(xk*xk1');mean(xk1*xk'),mean(xk1*xk1')];
P=[mean(dk*xk');mean(dk*xk1')];
Xk=[xk;xk1];
W=[0;0];
ek=mean(dk*dk')+W'*R*W-2*P'*W;
for i=1:1:10000
    W=W+2*0.05*ek*Xk;
end
plot(i,W)