已知x,y属于R,满足2≤y≤4-x,x≥1,则x^2+y^2+2x-2y+2/xy-x+y-1的最大值(x^2+y^2+2x-2y+2)/(xy-x+y-1)
问题描述:
已知x,y属于R,满足2≤y≤4-x,x≥1,则x^2+y^2+2x-2y+2/xy-x+y-1的最大值
(x^2+y^2+2x-2y+2)/(xy-x+y-1)
答
原式=[(x+1)²+(y-1)²]/[(x+1)(y-1)]
记a=x+1,b=y-1,有2=