Question

已知函数f(x)=x2/x-1(x>1),则f(x)的最小值等于

Answer 1

f(x)=x^2/(x-1)=(x+1)+1/(x-1)=(x-1)+1/(x-1) +2≥2+2=4

当且仅当x-1=1/（x-1）,即x=2时,有最小值f（x）min=4