1. y=(x+3)/(x+1)
=(x+1+2)/(x+1)
=1+2/(x+1)
因为2/(x+1)的值域不为0,
因此y的值域不为1
2. y=x/(x+1)
=(x+1-1)/(x+1)
=1-1/(x+1)
因为1/(x+1)的值域不为0
故y的值域不为1.