Matematika

Pertanyaan

No44

Jika vektor a = i + 3j -2k dan b = 4i -2j + 4k. Nilai a.b adalah...
Select one:
a. 15
b. -4
c. -10
d. 12
e. 3

2 Jawaban

  • a = i + 3j - 2k
    b = 4i - 2j + 4k

    a.b = (1)(4) + (3)(-2) + (-2)(4)
    a.b = 4 - 6 - 8
    a.b = - 10

    C
  • Vektor

    a = (1) i + 3j - 2k
    b = 4i - 2j + 4k

    a . b
    = (a1)(b1) + (a2)(b2) + (a3)(c3)
    = (1)(4) + (3)(-2) + (-2)(4)
    = 4 - 6 - 8
    = -10

    C.

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