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题目已知一个等差数列{a_n}的前10项和为310,前20项和为1220,由这些条件能确定这个等差数列的前n项和的公式吗?这是人教A版高中数学必修5中一道关于等差数列求和的例题,下面通过5种不同的解法来看等差数列求和的问题.
Problem Is it known that the first 10 terms of an arithmetic progression {a_n} and the formula for the first n terms sum of 310 for the first 20 terms and 1220 for the arithmetic progression of this arithmetic progression? Mathematical compulsory 5 in a series of arithmetic on the difference between the sum of the example, the following five different solutions to see the arithmetic sequence of the sum of the problem.