我们知道数列通项 an 具有如下两个常见的基本变形式 :差式变形式 :an=(an- an-1 ) (an+ 1 - an-2 ) +…+(a2 - a1 ) +a1 . 1商式变形式 :an=anan-1· an-1 an-2·…· a3 a2· a2a1·a1 . 21式可以应用于求递推关系式为 :an+ 1 =an+g(n)型数列的通项公式 ;2式可以应用于求递推 We know that the general term an has the following two basic variants: the differential form: an=(an-an-1) (an+ 1 - an-2) +...+(a2 - a1) +a1 . 1 The variants of the quotient are: an=anan-1·an-1 an-2····· a3 a2·a2a1·a1 . The formulae can be applied to the recursion formula: an+ 1 =an+g(n) type sequence The general term formula; 2 formula can be applied to recursion