求y=(x^2-x+2)/(x^2+x+2)的值域

求y=(x^2)+2x(x≥0) y=-x+2x(x 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 Y=X^2X (X>0) 求导Y=X^2X (X>0) 求d(Y)/d(X) y=(2x*x-2x+3)/(x*x-x+1),求值域? 已知x+y=a,2x-y=-2a,求[（x/y-y/x)/(x+y)-x(1/x-1/y)]/[(x+1)/y]的值 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 求微分 y=x^(x^2) y=x^2x,求dy 已知:x+2y=2011 求代数式{(x^+y^)-(x-y)^+2x(x+y)}/2x的值 x+y=1,xy=-1/2,求x(x+y)(x-y)-x(x+y)2 y=x^x的导函数是：y'=x^x(Inx+1)我知道怎样求.但为什么不可以这样求.y=x^x=x*x*x*x*x*x*...*x(x个x) 则y'=(x')*x^(x-1)+x*(x')*x^(x-2)+.=x^x 求值域 1,y=(x+2)/(x*x+3x+6) 2,y=3x/(x*x+4) x+2y=2x+y+1=7x-y 求：2x-y? f(x+y,x-y)=(x^2-y^2)/2xy,求f(x,y)! x^2+y^2=15,x+y=7,x＞y,求x-y f(x+y,y/x)=x^2-y^2求f(x,y) 已知x≠y,x^2-x=y^2-y,求x+y的值.