X+1/X-1>0(X+1)(X-1)>0定义域X<-1或X>1F(-X)=loga(1-X/-X-1)=loga(X-1/X+1)=loga(X+1/X-1)-1次方=-loga(X+1/X-1)=-F(X)所以这是奇函数