0.5x+0.7y=35 x+0.4y=40
0.5x+0.7y=35,x+0.4y=40.求x=?,y=?
(x+y)(x+2y)(x+3y)(x+4y)=-40
已知X,Y独立,P(x)=0.5,p(x+y)=0.7,求p(y).
0.58=(0.5x+0.7y)/(x+y)求X比y怎么求
老师.0.58=(0.5x+0.7y)/(x+y)求X比y怎么求
二元函数f(x,y)=x+y/x-y,求f(y/x,x/y)
[x(x-y)-y(x-y)+(x+y)(x-y)]÷2x其中x=2012 y=2013
) y=cos(x-y)
x+y=5; x^y+y^x=17
因式分解下列式子:x(x-y)+y(y-x)=?
Matlab编程问题 cos(x*y)*cos(x*(1-y))-0.5x*sin(x*y)*sin(x*(1-y))=
1.先化简,再求值:(2X+Y)^2-(2X-Y)(X+Y)-2(X-2Y)(X+2Y),其中X=0.5,Y=-2