Дана арифметическая прогрессия:-4,-2,0..Найдите сумму первых десяти ее членов. - Дата: 08.11.2019, Автор: ingridserrano - Znanija.Site

Дана арифметическая прогрессия:-4,-2,0..Найдите сумму первых десяти ее членов.
- Предмет:
  Алгебра
- Автор:
  ingridserrano
- 5 лет назад

Ответы 1

а1=-4a2=-2d=a2-a1=-2 - (-4)=-2+4=2S={ (2a1+ (n-1)*d)*n/2S10={2*-4+(10-1)*2*10)/2=(-8+18)*10/2=10*10/2=100/2=50
- Автор:
  jetshepherd
- 5 лет назад
- 0
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