Matematika

Pertanyaan

persamaan logaritma
a. log (log x + 3) = log 2
b. 4log2^x = x
c. 3log^2x-9.3logx-10=0

2 Jawaban

  • jawab
    a)

    log (log x + 3) = log (2)
    log x +  3 = 2
    log x = -1
    x = 10^(-1)
    x = 0,1

    b)
    ⁴ log  2ˣ  = x
    4ˣ  = 2ˣ
    x= 0

    c)
    ³log² x - 9. ³log x -10 = 0
    misalkan ³log x = y
    (3log x)² - 9(³log x) - 10 =0
    y² - 9y -10 = 0
    (y -10)(y +1)= 0
    y = 10 atau y = -1

    y= 10 → ³log x = 10 → x = 3¹⁰
    y = -1 → ³log x = -1  → x = 3⁻¹ →  x = 1/3
    HP x = { 3¹⁰, 1/3}


  • a. Log x+3=2
    10²=x+3
    100=x+3
    x=100-3
    =97
    b. ⁴log 2^x=x atau soalnya 4.log 2^x?
    C. Misal ³log x=y
    y²-9y-10=0
    (y-10)(y+1)=0
    y=10 atau y=-1
    ³log x=10
    x=3^10
    =3^5.3^5=243.243=59049
    ³logx=-1
    3^-1=x
    x=1/3

Pertanyaan Lainnya