y等于2加x减x的平方的极值
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1/2再答:再问:谢谢了,问题解决了
x加y的平方等于9,x减y的平方等于5两式相减得:4xy=9-5=4xy=1
x^2+2x+y^2-6y+10=0=(x^2+2x+1)+(y^2-6y+9)=0=(x+1)^2+(y^2-6y+3^2)=0=(x+1)^2+(y-3)^2=0x=-1y=3xy=-3
该试可以这样写:(x-1)的平方加(y+2)的平方等于0.所以X等于1,Y等于-2.那2X加Y等于0了.
再问:姐姐,你多大啦,再答:20再问:哦哦,你家在哪呀,你当我姐姐好不好,?再问:^ω^再问:姐姐,你不说话我就当你默认了哈,!哈哈,姐,!再答:O(∩_∩)O再答:姐姐现在比较忙哦再问:
x^2-2x+y^2+6y+10=0x^2-2x+1+y^2+6y+9=0(x-1)^2+(y+3)^2=0x-1=0,y+3=0x=1,y=-3(x-y)/(x+y)=4/(-2)=-2
y=4x³-x²-2xy'=12x²-2x-2=0(3x+1)(2x-1)=0x=-1/3,x=1/2由二次函数的性质可知x1/2,y'=12x²-2x-2>0
x^2+2xy+y^2=25===>(x+y)^2=5^2===>x+y=±5(x-y)^2-3x+3y+2=0===>(x-y)^2-3(x-y)+2=0===>[(x-y)-1]*[(x-y)-2
x的平方加2x加1减y的平方=(x+1)²-y²=(x+y+1)(x-y+1)
y'=3x²-2xy'
问题求什么?再问:求x加y的值再答:x^2-2x+1+y^2-6y+9=0(x-1)^2+(y-3)^2=0x=1y=32x+3y=11
x²-4y²+2x-4y=(x+2y)(x-2y)+2(x-2y)=(x-2y)(x+2y+2)
x^2+4x+y^2-2y+5=0(x^2+4x+4)+(y^2-2y+1)=0(x+2)^2+(y-1)^2=0x=-2,y=1x^2+y^2=(-2)^2+1^2=4+1=5
3∵x/y=1/2∴y=2x故(x^2+2xy+y^2)/(x^2-xy+y^2)=(x+y)^2/(x^2-xy+y^2)=(x+2x)^2/(x^2-x·2x+4x^2)=9x^2/(3x^2)=
(x-2y)²=(x²-4xy+4y²)=(x²+4xy+4y²)-8xy=(x+2y)²-8xy∴A=-8xy或者记住(x减2y)的平方-
x²+y²=x²-xy+y²+xy=3+5=82x²+xy+3y²=2x²-2xy+3y²+3xy=2(x²-
x+y=2x^2-y^2+4y=(x+y)(x-y)+4y=2x-2y+4y=2x+2y=2(x+y)=4
∵x的平方加xy等于负5,xy加y的平方等于9∴x的平方减y的平方=(x²+xy)-(xy+y²)=-5-9=-142x的平方加3xy加y的平方=2(x²+xy)+(xy