设X>=1 Y>=1证明X+Y+1/XY
设X>=1 Y>=1证明X+Y+1/XY
已知xy>0,证明xy+xy/1+x/y+y/x>=4
设x≥1,y≥1,证明:x+y+1xy≤1x+1y+xy
设X,Y属于正实数,xy-(x+y)=1,则x+y最小值
设变量xy满足 x+y-3 x-y+1 3x-y+5 z=x+y/x
设x,y,z∈R+,xy+yz+xz=1,证明不等式:(xy)^2/z+(xz)^2/y+(yz)^2/x+6xyz≥x
已知x+y=3 xy=-5 求x设abc=1 求x²+3xy+2y²/x²y+2xy
设|X-2|+(Y+1/4)^2=0,试求代数式X^2(X^2-XY+Y)-X(X^3-2X^2Y+XY-1)
Z=x*sin xy+e^x+y或设y=(x)是由方程xy+sin x+sin y=1确定,求y”
用均值不等式证明:x方+y方>=x+y+xy-1
证明 当x+y+z=1时,x/yz+y/xz+z/xy≥9
设 e^(x+y) - xy = 1,求 dy/dx \ x=0 y=0