已知实数x,y满足,x^2+2y^2+2x+2=2xy,试求x-y-x^y的值
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解决时间 2021-03-17 09:46
- 提问者网友：辞取
- 2021-03-16 17:30
已知实数x,y满足,x^2+2y^2+2x+2=2xy,试求x-y-x^y的值
最佳答案
- 五星知识达人网友：一叶十三刺
- 2021-03-16 18:59
x^2+2y^2+2x+2=2xy
(x-y)^2+y^2+2x+2=0
(x-y)^2+(y+1)^2+2x-2y+1=0
(x-y)^2+2(x-y)+1+(y+1)^2=0
[(x-y)+1]^2+(y+1)^2=0
(x-y)+1=0 y+1=0
y=-1 x=-2
x-y-x^y=-1/2
(x-y)^2+y^2+2x+2=0
(x-y)^2+(y+1)^2+2x-2y+1=0
(x-y)^2+2(x-y)+1+(y+1)^2=0
[(x-y)+1]^2+(y+1)^2=0
(x-y)+1=0 y+1=0
y=-1 x=-2
x-y-x^y=-1/2
全部回答
- 1楼网友：罪歌
- 2021-03-16 20:16
x^2+2y^2+2x+2=2xy
(x-y)^2+y^2+2x+2=0
(x-y)^2+(y+1)^2+2x-2y+1=0
(x-y)^2+2(x-y)+1+(y+1)^2=0
[(x-y)+1]^2+(y+1)^2=0
(x-y)+1=0
y+1=0
y=-1
x=-2
所以所求的为-1/2
- 2楼网友：梦中风几里
- 2021-03-16 19:50
3y/(2x+2y) + 2xy/(x^2+xy)题目应该是这们的吧?
=3y/[2(x+y)]+2xy/[x(x+y)]
=(3y+4y)/[2(x+y)]
=7y/2(x+y)
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