如题所述
f(x) = x + 1/(x - 1)
= (x - 1) + 1/(x - 1) + 1
= [(1 - x) + 1/(1 - x)] + 1
≥ 2√[(1 - x) × 1/(1 - x)] + 1
= 3
f(x)min = 3 此时 x=2时 原式最小值为3