Logarithms
Logarithms can be considered as the inverse of indices.
If ax = y such that a > 0, a ≠ 1 then loga y = x
ax = y ↔ loga y = x
Take note of the following:
- Since a1 = a, loga a = 1
- Since a0 = 1, loga 1 = 0
- Loga 0 is undefined
- Logarithms of negative numbers are undefined.
- The base of logarithms can be any positive number except 1.
- Logarithms to the base 10 are known as common logarithms and are represented by log10 or lg.
Example:
Calculate the value of each of the following:
a) 1og2 64
b) log9 3
Solution:
a) Let x = log2 64
2x = 64
x = 6
b) Let x = log9 3
9x = 3
x = 
Have a look at the following video for more examples on solving logarithms.:
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