已知实数x y满足x方 y方=1,求y 2 x 1的取值范围

/>根据非负数之和为0得x+1=02(y-2）=0解得x=-1y=2于是x³-3xy+y³=-1³-3×(-1)×2+2³=-1+6+8=13

∵|2x-3y+1|+(x+3y+5)的二次方=0∴2x-3y+1=0x+3y+5=0x=-2y=-1∴（-2x*y）的二次方（-y的二次方）×6xy平方的值=4x⁴y*(-y²

x方y-xy方-x+y=56xy(x-y)-x+y=568(x-y)-x+y=567x-7y=56x-y=8x^2+y^2=(x-y)^2+2xy=64+2*8=80

因为3x方+xy-2y方=0,即（x+y)(3x-2y)=0,而x+y≠0,所以3x-2y=0原式=[（x+y)^2-4xy]/[(x+3y)(x-y)/(x+3y)(x-3y)=(x-3y)/(x+

k=(y+2)/(x+1)所以k就是过点(-1,-2)的直线的斜率x,y满足x^2+y^2=1所以就是求过点(-1,-2)的直线和单位圆有公共点是斜率的取值范围显然相切时有最值y+2=kx+kkx-y

根号和平方大于等于0,相加等于0,若有一个大于0,则另一个小于0,不成立所以两个都等于0所以x+y+7=0xy-5=0x+y=-7,xy=53x^2y^3+3x^3y^2=3x^2y^2(x+y)=3

再问：图片看不全再答： 能看到了吧？

∵3x+4y-10=0∴y=(10-3x)/4∴x²+y²=x²+(100-60x+9x²)/16=(25x²-60x+100)/16=[25(x-6

x=1/(2+√3)xy=1y=(2+√3)x=1/(2+√3)x=(2-√3)/(2+√3)(2-√3)x=2-√3(x^2y-xy^2)/(x^2-y^2)=xy(x-y)/(x+y)(x-y)=

5x²-3xy+1/2y²-2x+1/2y+1/4=0两边乘以2得：10x²-6xy+y²-4x+y+1/2=0配方得：（3x-y-1/2)²+（x-

已知x,y满足方程组x方+2y=5,(1)x-y=-1(2)(1)+(2)*2x²+2x-3=0解得x1=1x2=-3代入(2)y1=2y2=-21.x1=1y1=2时x+y分之x的三次方-

x+y=15两边平方x²+2xy+y²=225所以2xy=225-(x²+y²)=12xy=6所以原式=113-6=107

很高兴为你解答,这个有两种可能一：X是2,Y是6二：X是6,Y是2.但是计算结果一样,第一个答案是96第二个答案是20希望楼主采纳,很详细,很辛苦啊!

2x²=x²+x²所以(x²-2xy+y²)+(x²+2x+1)=0(x-y)²+(x+1)²=0平方大于等于0,相加等

1/(x^4)+4/(y^4)xy=1,所以y=1/x即y^4=1/（x^4）代入原式,得到1/(x^4)+4(x^4)再由重要不等式,得到1/(x^4)+4(x^4)≥2(根号)1/(x^4)·4(

首先x3-y3=(x-y)(x2+xy+y2)其次x3-y3-3xy=1所以x3-y3=1+3xy=(x-y)(x2+xy+y2)x-y=(1+3xy)/(x2+xy+y2)=(1+3xy)/[(x-

ax+by≤（a^2+x^2）/2+(b^2+y^2)/2=(m+n)/2当且仅当a=x且b=y时取等号,最大值为（m+n）/2

x²+2xy-3y²=0(x+3y)(x-y)=0解得x=y或x=-3y又x,y为正数所以y=x；x=-3y舍(x²+xy+y²)/(x²-xy+y&

6已知x+y=2,x-y=1,求分式x方+2xy+y方分之x方-y方的值x方+2xy+y方分之x方-y方=(x+y)(x-y)/(x+y)²=(x-y)/(x+y)=1/27已知x分之1-y

2X方-4XY+4Y方-6X+9=0(x^2-4xy+4y^2)+(x^2-6x+9)=0(x-2y)^2+(x-3)^2=0所以有x-2y=0,x-3=0即有x=3,y=x/2=3/2x*根号8Y=