函数y=(x+1)/(x-1) 的值域为 A (x<1)U(x>1) B (-1,1) C (x<-1)U(x>1) D (x<-1)U(x>-1)理由 详细

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函数y=(x+1)/(x-1) 的值域为 A (x<1)U(x>1) B (-1,1) C (x<-1)U(x>1) D (x<-1)U(x>-1)
理由 详细

y=(x+1)/(x-1)
=1+2/(x-1)
2/(x-1)>0或2/(x-1)1或y

y=(x+1)/(x-1)=(x-1+2)/(x-1)=1+[2/(x-1)]≠1
故选A