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13问答网 > 如何上好《等差数列的前n项和》这节课

如何上好《等差数列的前n项和》这节课

2025-03-16 14:10:24

推荐回答（2个）

回答1：

等差数列你给他比作成一个梯形，第一项（首项）好比梯形最上面1行，最后一项比成最后一项，那么求和就类似于梯形的求面积，这样S=½（a+b)*h,这里的高就好比数列有多少个。
S=½（a+b)*h
S:求和
a:首项(a1)
b:尾项(an)
h:项数（n)
不行你试试看，这样做居然跟书上那个公式算出来结果一样。

回答2：

其实等差数列的前n项和其实不复杂，主要是了解其规律，明白公式的含义，就很能理解

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