Question

函數(shù)y=x+

4

x-1

(x＞1)的值域?yàn)開_____．

Answer 1

∵x＞1
∴x-1＞0
y=x+

4

x-1

=（x-1）+

4

x-1

+1≥2

(x-1) 4 x-1

+1=5
當(dāng)且僅當(dāng)x=3時(shí)取等號(hào)
故函數(shù)y=x+

4

x-1

(x＞1)的值域?yàn)閇5，+∞）
故答案為：[5，+∞）