Matematika

Pertanyaan

Bantu jawab yaa. pada segitiga ABC diketahui cos A=8/17 dan sin B=5/13. nilai tan C

2 Jawaban

  • Kelas 11 Matematika
    Bab Trigonometri Lanjut

    cos A = 8/17 → x/r

    y = √(r² - x²)
    y = √(17² - 8²)
    y = √(289 - 64)
    y = √(225)
    y = 15

    sin A = y/r
    sin A = 15/17

    sin B = 5/13 → y/r

    x = √(r² - y²)
    x = √(13² - 5²)
    x = √(169 - 25)
    x = √144
    x = 12

    cos B = 12/13

    Sudut A + sudut B + sudut C = 180°
    A + B = 180° - C
    sin (A + B) = sin (180° - C)
    sin A cos B + cos A sin B = sin C
    15/17 . 12/13 + 8/17 . 5/13 = sin C
    180/221 + 40/221 = sin C
    sin C = 220/221 → y/r

    x = √(r² - y²)
    x = √(221² - 220²)
    x = √48.841 - 48.400)
    x = √441
    x = 21

    tan C = y/x
    tan C = 220/21
  • Cos A = 8/17
    tan A = 15/8

    sin B = 5/13
    tan B = 5/12

    tan C = tan (A+B)
    = \frac{ \frac{15}{8} + \frac{5}{12} }{1 - \frac{15}{8} \frac{5}{12} }
    = \frac{ \frac{220}{96} }{ \frac{21}{96} }
    = \frac{220}{21}

    #semogamembantu

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