一道分式计算题!x^2+y^2+z^2 ----------------- =1 且x,y,z不等于0,求证1/x + 1/y +1/z=0 (x+y+z)^2 (分号不会打就凑合看看吧,还有我是初中生.)

问题描述:

一道分式计算题!
x^2+y^2+z^2
----------------- =1 且x,y,z不等于0,求证1/x + 1/y +1/z=0
(x+y+z)^2
(分号不会打就凑合看看吧,还有我是初中生.)

x^2+y^2+z^2
----------------- =1
(x+y+z)^2
x^2+y^2+z^2 =(x+y+z)^2 =x^2+y^2+z^2+2xy+2xz+2yz
2xy+2xz+2yz=0,xy+xz+yz=0;且x,y,z不等于0,两边同时除以xyz,得1/x+1/y+1/z=0
得证:1/x + 1/y +1/z=0

(x+y+z)^2 =x^2+y^2+z^2+2(xy+yz+xz)
=x^2+y^2+z^2
so:(xy+yz+xz)=0
1/x + 1/y +1/z=(xy+yz+xz)/xyz=0
注意我的回答和年清晰简单哦

x^2+y^2+z^2
----------------- =1 且x,y,z不等于0,
(x+y+z)^2
所以x^2+y^2+z^2 =(x+y+z)^2
2xy+2xz+2yz=0
xy+xz+yz=0
两边同除以xyz得
1/x+1/y+1/z=0

(x^2+y^2+z^2)/(x+y+z)^2 =1
x^2+y^2+z^2=x^2+y^2+z^2+2xy+2yz+2xz
xy+yz+xz=0
因为x,y,z不等于0,同除以xyz
1/z+1/x+1/y=0

(x^2+y^2+z^2)/ x+y+z)^2=1(x^2+y^2+z^2 )/(x^2+y^2+z^2+2xy+2xz+2yz)=1x^2+y^2+z^2=x^2+y^2+z^2+2xy+2xz+2yz2xy+2xz+2yz=0xy+xz+yz=0(xy+xz+yz)/xyz=01/x + 1/y +1/z=0

x^2+y^2+z^2 =(x+y+z)^2
xy+yz+xz=0
两边同除以xyz,即得结果