Арифметическая прогрессия S10 = 50 a1= -4 d - ? - №16231975

Арифметическая прогрессия
S10 = 50
a1= -4
d - ?
- Предмет:
  Алгебра
- Автор:
  orlandoobjy
- 6 лет назад

Ответы 1

S₁₀=50 a=-4 d - ?n=10S=(2a₁+d(n-1)*n/2=50(2*(-4)+d(10-1)*10)/2=50(-8+d*90)/2=50-40+45d=5045d=90d=2.Ответ: d=2.
- Автор:
  vincent89
- 6 лет назад
- 0
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