Question

aplicando a definição determine o valor

a) log 8 =
2

b) log =⅛
½

c) log 81 =
⅓

d) log =2
5

e) log =3
7

f) log =5
9

Answer 1

a) log 8 ==> 2^x = 8 ==> 2^x = 2^3 ==> x= 3
        2
=======================================================
b) log x =⅛  ==> x= (1/2)^1/8 ==> x = (2^-1)^1/8==> x = 2^- 1/8
       ½
======================================================
c) log 81 = x ==> 1/3^x = 81 ==> (3^-1)^x = 3^4=> - x = 4(-1) ==> x = - 4
⅓
======================================================
d) log x = 2 ==> x = 5^2 ==> x = 25
        5
==================================================
e) log x = 3 ==> x = 7^3 ==> x = 343
        7
===================================================
f) log x = 5 ==> x = 9^5 ==> x = (3^2)^5 ==> x = 3^10
9