доказать: sin3A=3sinA-4sin^3A - Дата: 08.12.2019, Автор: malachi - №11333806

доказать: sin3A=3sinA-4sin^3A
- Предмет:
  Математика
- Автор:
  malachi
- 6 лет назад

Ответы 1

sin3α = sin(α+2α) = sinα·cos2α + cosα·sin2α = sinα·(cos²α - sin²α) + cosα·(2sinαcosα) = cos²αsinα - sin³α + 2cos²αsinα = 3cos²αsinα - sin³α = =3sinα(1 - sin²α) - sin³α = 3sinα - 3sin³α - sin³α = 3sinα - 4sin³α
- Автор:
  grant33
- 6 лет назад
- 0
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