2x^2 y^2 5z^2-zxy 2yz=1正交
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/30 08:49:12
![2x^2 y^2 5z^2-zxy 2yz=1正交](/uploads/image/f/262434-66-4.jpg?t=2x%5E2+y%5E2+5z%5E2-zxy+2yz%3D1%E6%AD%A3%E4%BA%A4)
(y-z)^2+(z-x)^2+(x-y)^2=(x+y-2z)^2+(y+z-2x)^2+(z+x-2y)^2[(y-z)^2-(y+z-2x)^2]+[(z-x)^2-(x+z-2y)^2]+[(
∑是循环和例如∑a=a+b+c∑a^2=a^2+b^2+c^2∑(z-y)(x-y)/(x+y-2z)(y+z-2x)=∑(z-y)(x-y)(x+z-2y)/(x+y-2z)(y+z-2x)(x+z
有这样的公式:a^3+b^3+c^2-3abc=(a+b+c)(a^2+b^2+c^2-ab-bc-ca)左边减右边,证明:(x+y-2z)^3+(y+z-2x)^3+(z+x-2y)^3-3(x+y
x2-(y+z)2=(x+y+z)(x-y-z)=8x+y+z=2所以x-y-z=8÷2=4
∵x-2y+z=(x-y)-(y-z),x+y-2z=(y-z)-(z-x),y+z-2x=(z-x)-(x-y).设x-y=a,y-z=b,z-x=c,则原式=-ac/(a-b)(b-c)+(-ba
正整数?取对数即证:2xlnx+2ylny+2zlnz>(y+z)lnx+(x+z)lny+(x+y)lnzx>y>z,lnx>lny>lnz由排序不等式得xlnx+ylny+zlnz>ylnx+zl
答:Zx=2xf1'+yf2'Zxy=2x²f12''+f2'+xyf22''
Dz/Dx=2f'+g1+yg2,DDz/DxDy=-2f"+yg12+y^2*g22.
设a=x-y,b=y-z,-a-b=z-x(y-z)平方+(x-y)平方+(z-x)平方=(y+z-2x)平方+(z+x-2y)平方+(x+y-2z)平方b^2+a^2+(-a-b)^2=(-a-b-
你确定是化简为Zuv=0吗?我只能得到某个a,化简为Zuu=0Zx=Zu*Ux+Zv*VxZxx=(Zu*Ux+Zv*Vx)x=(Zu+Zv)x=(Zu)x+(Zv)x=Zuu*Ux+Zuv*Vx+Z
4X^2-8X+1+8X^2+8X=12X^2-48X+48+348X=54X=9/8
x^2(y-z)+y^2(z-x)+z^2(x-y)=x^2y-x^2z+y^2z-y^2x+z^2x-z^2y=y(x^2-z^2)-xz(x-z)-y^2(x-z)=y(x+z)(x-z)-xz(
第二个分母写错了?(y-x)(z-x)/(x-2y+z)/(x+y-2z)+(z-y)(x-y)/(x+y-2z)/(y+z-2x)+(x-z)(y-z)/(y+z-2x)/(x-2y+z)=1
25xy^2z^2(x+y-z)-30xyz(z-x-y)^2+5xyz^3(z-x-y)=25xy^2z^2(x+y-z)+30xyz(x+y-z)^2-5xyz^3(x+y-z)=5xyz(x+y
(y+z-x)/{x^2-(y+z)^2}=(y+z-x)/[(x-y-z)(x+y+z)]=-(x-y-z)/[(x-y-z)(x+y+z)]=-1/(x+y+z)
=x²(y-z)+y²(z-x)+z²(x-z+z-y)=(y-z)(x²-z²)+(z-x)(y²-z²)=(y-z)(x-z)
x^4(y-z)+y^4(z-x)+z^4(x-y)=xy(x^3-y^3)+yz(y^3-z^3)+zx(z^3-x^3)=xy(x^3-y^3)+yz(y^3-z^3)-zx[(x^3-y^3)+
∵x2-3xy+4y2-z=0,∴z=x2-3xy+4y2,又x,y,z为正实数,∴zxy=xy+4yx-3≥2xy•4yx-3=1(当且仅当x=2y时取“=”),即x=2y(y>0),∴x+2y-z
根据公式(a+b+c)^2=a^2+b^2+c^2+2ab+2bc+2ac公式展开:得到(x^2+y^2+z^2=2xy-2yz-2xz)-(x^2+y^2+z^2-2xy-2yz+2xz)合并同类项