实例,是归纳的基础、论证的依据、说理的帮手.数学当然不会丢了这位朋友,初步想想,至少在以下几方面它们有着深厚的“友谊”.举例,验证记忆不清的公式.当我们对扇形面积公式S=21rl(r—半径,l—弧长)感到有点模糊时,可举半圆(当l=πr时)验证一下;三角形面积是否可用!s(s-a)(s-b) Examples are the basis for induction, the basis for argumentation, and the helper for reasoning. Of course, mathematics will not lose this friend. Initially think about it, at least in the following aspects they have a profound “friendship.” For example, to verify the memory formula When we feel a bit fuzzy about the sector area formula S=21rl (r-radius, l-arc length), we can check the semicircle (when l=πr) to verify; whether the triangle area is available!s(sa)(sb)