证明若X和Y不相关,则有D(X+Y)=DX+DY成立
证明若X和Y不相关,则有D(X+Y)=DX+DY成立
如题:随机变量X与Y不相关是D(X+Y)=DX+DY成立的充要条件,求证!
随机变量满足D(X+Y+Z)=DX+DY+DY.则A,X,Y,Z相互独立 B,任意两个不相关
d(x+y)=dx+dy,
d^2y/dx^2=(dy/dx)'×(dy/dx),另外请解释下dx,dy的含义,dx和dy是指x=...和y=...
微积分.若x^y=y^x,则dy/dx.
若x与y相互独立,则d(x-y)=dx-dy
d{cos(x-y)=sin(x-y)(dx-dy)这里dx-dy是什么意思呢?
y=[sin(x^4)]^2,则dy/dx=?,dy^2/dx^2=?,dy/d(x^2)=?
dy/dx=x+y
概率论问题,随机变量X,Y独立,请问D(XY)=DX.DY吗,请给出证明.
从(dx)/(dy)=1/y '导出:(d^2x)/(dy^2)=-y''/(y')^3