Logarithm(log, lg, ln)
If b = ac <=> c = logab, a,b,c are from R, b > 0, a > 0, a ≠ 1
a
For example: 23 = 8 => log28 = 3
There are standrart notation of logarithm if the base is 10 or e.
log10b = lg b
logeb = ln b
logeb = ln b
Logarithm graph
It shows that when x = 1, log = 0; when x -> 0 => log -> -∞; when x -> ∞ log -> ∞
Logarithm(log) properties
logaa = 1
loga(b.c) = logab + logac
loga(b/c) = logab - logac
logabn = n.logab
logba = 1/logab
logbc = logac/logab
logab = logac <=> b = c
loga(b.c) = logab + logac
loga(b/c) = logab - logac
logabn = n.logab
logba = 1/logab
logbc = logac/logab
logab = logac <=> b = c
More about logarithms in the maths forum












