Matematika

Pertanyaan

Sin 240°+ sin 225°+ cis 315°

2 Jawaban

  • Sin 240° = (270-240) = -sin 30° = - ½
    Sin 225° = (270-225) = -sin 45° = - ½√2
    Cos 315° = (360-315) = cos 45° = ½√2
    = Sin 240 + sin 225 + cos 315
    = -½ + -½√2 + ½√2
    = -1 + ½√2
    = - ½√2
  • sin 240°+ sin 225°+ cos 315°
    = -1/2
    √3 + (-1/2√2) + 1/2√2
    = -1/2√3 - 1/2√2 + 1/2√2
    = -1/2√3

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