DX=4,DY=9,Pxy=0.4,求D(x+y)及D(x-y)?
DX=4,DY=9,Pxy=0.4,求D(x+y)及D(x-y)?
两个随机变量X与Y,已知DX=25,DY=36,Pxy=0.4,求Cov(x,y)及D(X-Y)
d(x+y)=dx+dy,
d/dx((x^2+y^2)^2)=d/dx(x^2-y^2),求(化简)dy/dx=?
设y=2arctany/x,求dy/dx,dy^2/d^2x.
d{cos(x-y)=sin(x-y)(dx-dy)这里dx-dy是什么意思呢?
已知dx/dy=1/y′,求d(2)y/d x^2?
求微分方程的通解:x^2(d^2y/dx^2)=(dy/dx)^2+2x(dy/dx)
y=[sin(x^4)]^2,则dy/dx=?,dy^2/dx^2=?,dy/d(x^2)=?
dx/dy=1/y',求d^2x/dy^2 .为什么d^2x/dy^2不等于dx/dy求导?一个是二阶导数,一个是一阶导
已知dy/dx=y',求d^2x/dy^2.
已知dx/dy=1/y’ 求d²x/dy²