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先化简再求值 (x+1分之x +x^2-1分之x+1)除以(x^2+x分之x^2+1)

来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/05/28 03:52:48
先化简再求值 (x+1分之x +x^2-1分之x+1)除以(x^2+x分之x^2+1)
如题..
(x+1分之x +x^2-1分之x+1)除以(x^2+x分之x^2+1)
=(x/x+1 +x+1/(x+1)(x-1))/(x^2+1/x^2+x)
=(x/x+1 +1/x-1)*(x^2+x/x^2+1)
=((x(x-1)+1)/(x+1)(x-1))*(x^2+x/(x^2+1))
=((x^2-x+1)/(x+1)(x-1))*(x(x+1)/(x^2+1))
=x(x^2-x+1)/(x-1)(x^2+1)
=(x^3-x^2+x)/(x^3+x-x^2-1)
=(x^3-x^2+x-1+1)/(x^3-x^2+x-1)
=1+1/(x^3-x^2+x-1)
再将x的值代入,就可计算了.
再问: 但他的答案怎么是x-1分之x 。。。。
再答: 不好意思,算错了。 应是 (x+1分之x +x^2-1分之x+1)除以(x^2+x分之x^2+1) =(x/x+1 +x+1/(x+1)(x-1))/(x^2+1/x^2+x) =(x/x+1 +1/x-1)*(x^2+x/x^2+1) =((x(x-1)+x+1)/(x+1)(x-1))*(x^2+x/(x^2+1)) =((x^2-x+x+1)/(x+1)(x-1))*(x(x+1)/(x^2+1)) =x(x^2+1)/(x-1)(x^2+1) =x/(x-1)