已知x>1则y=x+1⼀(x-1)的最小值为

2024-12-29 01:07:59
推荐回答(4个)
回答1:

解:因为x>1,所以x-1>0,所以y=x+1/(x-1)=(x-1)+1/(x-1)+1>=2√[(x-1)×1/(x-1) +1=2+1=3
当且仅当x-1=1/(x-1),即x=2时y取得最小值3.

回答2:

y=x+1/(x-1)

=x-1+1/(x-1)+1
>=2√(x-1)*1/(x-1)+1
=2+1
=3
即最小值=3

回答3:

x-1>0
所以y=(x-1)+1/(x-1)+1>=2根号 [(x-1)*1/(x-1)]+1=3
所以最小值是3

回答4:

∵x>1

∴y=x+1/(x-1)=x-1+1/(x-1)+1≥2√[(x-)*(1/(x-1))]+1=3

当且仅当x-1=1/(x-1)即:x=2时y=x+1/(x-1)取得最小值3