问题标题:
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..
问题描述:
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..
常富洋回答:
(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.
齐梅回答:
但他的答案怎么是x-1分之x。。。。
常富洋回答:
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)
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