原文題目:Let f(0) = 0 and f(x) = 1/x if 0 < x ≤ 1. Show that f is not integrable on [0, 1]. [Hint: Show that the first term in the Riemann sum, f(x1*) Δx, can be made arbitrarily large.]
網路上的解法:https://www.slader.com/discussion/question/let-and-if-show-that-is-not-integrable-on-hint-show-that-the-first-term-in-the-riemann-sum-can-be-ma/
我不太清楚為甚麼他寫x1*=1/n^2?