Re: [中學] 100台南二中教甄一題
※ 引述《forbeat (殘酷的現實面！)》之銘言：
: x+y+z=(1/x)+(1/y)+(1/z)=1，試證x,y,z至少有一個是1
: ps.請問南二中會放全部題目跟答案嗎？
: 考爆了想再算一遍 82分離我真遙遠.....
1/x+1/y+1/z=1/(x+y+z)
yz(x+y+z)+zx(x+y+z)+xy(x+y+z)=xyz
x^2*y+xy^2+y^2*z+yz^2+z^2*x+zx^2+2xyz=0
(x+y)(y+z)(z+x)=0
若x+y=0 則z=1
y+z=0 x=1
z+x=0 y=1
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