1*3*5+5*7*9+……97*99*101

学习 时间:2026-08-14 07:22:35 阅读:5401
1*3*5+5*7*9+……97*99*101

最佳回答

儒雅的白昼

跳跃的白猫

2026-08-14 07:22:35

待求和式=∑(4n+1)(4n+3)(4n+5),n从0到24。用裂项相消法,(4n+1)(4n+3)(4n+5) = 1/8 *[(4n+1)(4n+3)(4n+5)(4n+7) - (4n-1)(4n+1)(4n+3)(4n+5)]所以∑(4n+1)(4n+3)(4n+5),n从0到24=1/8 * [97*99*101*103 - (-1)*1*3*5]=1/8 *[999* 10^5 + 24]=12487503

最新回答共有2条回答

  • 哭泣的老虎
    回复
    2026-08-14 07:22:35

    待求和式=∑(4n+1)(4n+3)(4n+5),n从0到24。用裂项相消法,(4n+1)(4n+3)(4n+5) = 1/8 *[(4n+1)(4n+3)(4n+5)(4n+7) - (4n-1)(4n+1)(4n+3)(4n+5)]所以∑(4n+1)(4n+3)(4n+5),n从0到24=1/8 * [97*99*101*103 - (-1)*1*3*5]=1/8 *[999* 10^5 + 24]=12487503

上一篇 Nice to see you.先回答,

下一篇 宇宙的照片是怎么拍出来的?