已知函数f(x)=(k+1)/x(k<0)，求使得f(x+?
2008-06-29 18:29:23b***
已知函数f(x)=(k+1)/x(k<0)，求使得f(x+k)>1成立的x的集合已知函数f(x)=(k+1)/x(k0)，求使得f(x+k)1成立的x的集合：f(x)=(k+1)/x,(k1
---?
最佳回答
f(x)=(k+1)/x,(k1
--->(k+1)/(x+k)>1
--->1-(k+1)/(x+k)(x-1)/(x+k)1(k<-1)时,12008-06-29 18:48:42
解：
f(x+k)=（k+1)/(x+k)>1
[(k+1)/(x+k)]-1>0
[(k+1)/(x+k)]-(x+k)/(x+k)>0
(x-1)/(x+k)1时 ，k-1
k<0(题意)
-12008-06-29 18:46:16
(K+1)/(X+K)>1
(K+1-X-K)/(X+K)>0
(X-1)(X+K)-1 -K2008-06-29 18:37:24
很赞哦！ (67)
