Matematika

Pertanyaan

Jika x^1/2 + x^-1/2 = 2
Nilai x^2 + x^-2 adalah

1 Jawaban

  • x^1/2 + x^-1/2 = 2
    (x^1/2 + x^-1/2)^2 = 2^2
    (x^1/2)^2 + 2 . x^1/2 . x^-1/2 + (x^-1/2)^2 = 4
    x + 2 + x^-1 = 4
    x + x^-1 = 2

    (x + x^-1)^2 = 2^2
    x^2 + 2 . x . x^-1 + x^-2 = 4
    x^2 + 2 + x^-2 = 4
    x^2 + x^-2 = 2

    Ingat : (a + b)^2 = a^2 + 2ab + b^2

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