Matematika

Pertanyaan

jika alpha dan beta adalah akar akar persamaan kuadrat x²-6x+3=0 maka 1/alpha+1/beta adalah....

2 Jawaban

  • Misal :
    Alpha = a
    Beta = b

    1/a + 1/b
    = b/ab + a/ab
    = (b + a) / ab

    x^2 - 6x + 3
    Mengikuti :
    ax^2 + bx + c = 0 (ab ini bkn akarnya)
    a = 1
    b = -6
    c = 3

    Jmlh kdua akar
    = -b/a
    = -(-6) / 1
    = 6

    Hasil kali
    = c/a
    = 3/1
    = 3

    Maka :
    1/a + 1/b
    (b + a) / (ab)
    = 6/3
    = 2
  • x^2 - 6x + 3 = 0 => a = 1, b = -6, c = 3
    1/Alpha + 1/Beta = -b/c = -(-6)/3 = 2

    Kenapa bisa -b/c karena
    1/x1 + 1/x2 = (x2 + x1)/(x1.x2) = (-b/a)/(c/a) = -b/c

Pertanyaan Lainnya