The teaching of calculus is outspread from real number set, existence problem ran through the teaching all the time. This paper thoroughly discusses the basic properties of real number, introduces the general idea of solving the existence problem, and hope the students deeply realized the boundless charm of the mathematics thoughts and methods from the beginning of the calculus teaching.%大学微积分的教学内容是在实数集合上展开的．存在性问题贯穿微积分教学的始终．从深入讨论实数的基本性质开始，引入了求解存在性问题的一般思路．希望从微积分教学的一开始，就让学生深刻体会到数学思想方法的无穷魅力．
展开▼
