如果1,3,5,7,9等等是从1开始的奇数,那么前2019个奇数的和是多少？

2022-11-22 12:13

2022-11-22 15:26

等差数列 a1 = 1，d = 2，n = 2019
Sn = a1*n + n*(n-1)d/2
= n²
= 2019²
= 4,076,361

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