一、定义新的概念 例1定义“等和数列”:在一个数列中,如果每一项与它的后一项的和都为同一 个常数,那么这个数列叫做等和数列,这个常数叫做该数列的公和.已知数列{久}是等 和数列,且内二2,公和为5,那么al8的值为,这个数列的前n项和凡的计算公式 为 解析由题意可知:al+娇时解… First, define a new concept Example 1 Definition of “equal sum series”: In a sequence, if the sum of each item and its last item is the same constant, then the sequence is called equal sum series, this constant is called The series of public sums. The known sequence {{}} is a series of equal numbers, and within the second two, the common sum is 5, then the value of al8, the first n items of this series and the calculation formula for the series are resolved by the meaning of the problem: Al+ delicate solution...