在研究等差数列前ｎ项和的比值的过程中 ,发现两类规律 ,一类是两个等差数列前ｎ项和的比值 ,另一类是等差数列前ｍ项和与前ｎ项和的比值 .1 .设等差数列 {ａｎ}的首项为ａ1,公差为ｄ1,等差数列 {ｂｎ}的首项为ｂ1,公差为ｄ2 ,它们前ｎ项的和分别为Ｓｎ、Ｔｎ,则它们前ｎ项和的 In the process of studying the ratio of the first n sums of the arithmetic sequence, two types of laws were found. One is the ratio of the sums of the first n sums of two equal arithmetic sequences, and the other is the first m and the first n terms of the arithmetic progression. The ratio of . and .1. Let the first item of the arithmetic sequence {an} be a1, the tolerance is d1, the first item of the arithmetic sequence {bn} is b1, and the tolerance is d2. The sum of the first n terms is Sn, Tn. , then they are the first n terms and