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设xyz=1,求x/(xy+x+1)+y/(yz+y+1)+z/(zx+z+1)的值
已知实数a满足a^2+4a-8=0,求1/(a+1)-(a+3)/(a^2-1)×(a^2-2a+1)/(a^2+6a+9)的值
人气:228 ℃ 时间:2019-08-19 19:21:56
解答
1.xyz=1x/(xy+x+1)+y/(yz+y+1)+z/(zx+z+1)将x/(xy+x+1)中的1换为xyz得:=x/(xy+x+xyz)+y/(yz+y+1)+z/(zx+z+1)=1/(yz+y+1)+y/(yz+y+1)+z/(zx+z+1)=(1+y)/(yz+y+1)+z/(zx+z+1)将(1+y)/(yz+y+1)中的1换为xyz得:=(xyz+y)/...
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