错位相减法是数列求和中很重要的一种方法,一般情况下,若{a_n}为等比数列,{6_n)为等差数列,则求数列{a_n·6_n)的前n项和一般都用错位相减法.但是这种方法对运算能力的要求比较高,使用时容易出错,有没有其他方法呢?为此,笔者以2012高考江西卷第16题为例,将其各种解法整理如下,供同学们选择. Displacement subtraction method is an important method of sequence summation, under normal circumstances, if {a_n} for the geometric sequence, {6_n) for the arithmetic sequence, then the number of columns {a_n · 6_n) of the first n and general Are using dislocation subtraction method.But this method of computing power requirements are relatively high, easy to use error, there is no other way? To this end, the author of the 2012 Jiangxi entrance exam 16 as an example, the various solutions As below, for the students to choose.