摘要：We define the smallest positive real number as the number which is explicitly greater than zero and yet less than all other positive real numbers exce 阅读全文

摘要：From the perspective of analytical geometry, an interval is composed of infinitely many points, while after the length of an interval was defined, it is intuitively to believe its length is the sum of... 阅读全文

摘要：Dividing an unit interval $[0,1]$ into two equal subintervals by the midpoint $\dfrac {0+1} {2}=\dfrac {1} {2}$, denote the left subinterval by $I_{1} 阅读全文

摘要：视频解说 http://www.bilibili.com/video/av8565224/ 阅读全文

摘要：Given an infinite sequence (a1, a2, a3, ...), a series is informally the form of adding all those terms together: a1 + a2 + a3 + ···. To emphasize tha 阅读全文