4.2.2 Change of Base of Logarithms

Change of Base of Logarithms


    log a b= log c b log c a  and    log a b= 1 log b a  

Example
:
Find the value of the following:
a. log 25 100
b. log 3 0.45

Answer:

(a)   log 25 100= log 10 100 log 10 25 = log 10 10 2 log 10 25 = 2 1.3979 =1.431 (b)   log 3 0.45= log 10 0.45 log 10 3 = 0.3468 0.4771 =0.727
Example 1
Find the value of the following.
(a) log 4 8
(b) log 125 5
(c) log 81 27
(d) log 16 64





Example 2
Given that log p 3 = h   and log p 5 = k  , express the following in term of h and or k.
(a) log p 5 3

(b) log 15 75


1 thought on “4.2.2 Change of Base of Logarithms”

Leave a Comment