现行高中数学教材中给出了等差数列和等比数列的求和公式。而对于某些特殊的杂数列,我们也可以求出它们的和。现举例谈一谈求杂数列和的三种常用方法。一、利用“化归”法求和这种求和方法,是先寻求数列的通项公式,然后按照通项公式写出数列和的表达式。通常情况下,即可将原数列化归为等差数列或等比数列去求和。 In the current high school mathematics textbooks, sum formulas for arithmetic progressions and geometric progressions are given. For some special columns of the difference, we can also find their sum. For example, let’s talk about the three common methods for summing up the sums of the miscellaneous numbers. First, the use of “return to ” method of summing this summation method is to first search for a series of general terms formula, and then follow the general formula to write series and expressions. Normally, the original number can be classified as an arithmetic progression or a geometric progression.