随机向量(X,Y),有D(X)=36,D(Y)=25,协方差COV(X,Y)=12,则D(X-Y)=?求详解

问题描述:

随机向量(X,Y),有D(X)=36,D(Y)=25,协方差COV(X,Y)=12,则D(X-Y)=?
求详解