设x＞3,则函数fx=[4/(x-3)]+x的最大值为

Question

设x＞3,则函数fx=[4/(x-3)]+x的最大值为

Answer 1

设x＞3,则函数fx=[4/(x-3)]+x
没有最大值,x可以无穷大,函数值也无穷大,估计求最小值吧
fx=[4/(x-3)]+x =[4/(x-3)]+（x-3）+3≥2 √[4/(x-3)×（x-3）]+3=4+3=7
函数fx=[4/(x-3)]+x的最小值为7