function  ROmega=RO(Omega)
%這是個計算旋轉矩陣ROmega的函數;
    ROmega=zeros(3,3);
    ROmega(1,1)=1;
    ROmega(2,2)=cos(Omega);
    ROmega(2,3)=-sin(Omega);
    ROmega(3,2)=sin(Omega);
    ROmega(3,3)=cos(Omega);