急!f(x方+1\x方)=(1\x方)-1,求f(x)的解析式
问题描述:
急!f(x方+1\x方)=(1\x方)-1,求f(x)的解析式
答
f(x方+1\x方)=(1\x方)-1
用1\x方取代x方,得:f(1\x方+x方)=x方-1
两式相加,得:2f(x方+1\x方)=x方+(1\x方)-2
用x取代x方+1\x方,得:2f(x)=x-2
所以f(x)=x\2-1