Reference Data on Logarithms

Reference Data on Logarithms

This page contains

a short table of logs (base 10)
a table of constants relevant to logs
a list of log identities, including examples

A Short Table of Logarithms

x	log₁₀x
1.000	0.000
1.500	0.176
2.000	0.301
2.500	0.398
3.000	0.477
3.500	0.544
4.000	0.602
4.500	0.653
5.000	0.699
5.500	0.740
6.000	0.778
6.500	0.813
7.000	0.845
7.500	0.875
8.000	0.903
8.500	0.929
9.000	0.954
9.500	0.978
10.000	1.000

Constants

Constant	Value
e	2.718
log₁₀e	0.434
log₁₀2	0.301
log₂e	1.443
log_e2	0.693
log_e10	2.303
log₂10	3.322

Logarithmic Identities

Identity	Example of Use
a^y = x means y = log_ax	10^0.301 = 2.00
log ab = log a + log b	log 150 = log 100 + log 1.5= 2 + 0.176 = 2.176
log aⁿ = n log a	log sqrt(2) = ½ (log 2) = 0.150
log_ab = log_cb / log_ca	log_e 2 = log₁₀2/log₁₀e= 0.301/.434 = 0.693

Comments to Dr. Ernst W. Grundke