Logarithm
lastmod 2018-08-17created 2015-09-014 edits
The logarithm (log) is a kind of mathematical function that gives how many times a fixed base must be multiplied to produce a given number. It is known to have been invented by John Napier in the early 17th century to simplify multiplication and division. Because it makes calculations with complex units simple, it spread worldwide among scholars in many fields, along with inventions such as logarithm tables and the slide rule. In Korean it is also called daesu (對數), in the sense that it stands opposite the exponent.
Definition via exponential functions
When a > 0, a != 1, y > 0, if x and y are related by y = a^x, then "x is the logarithm of y to base a", written log_a y = x.
Natural logarithm
(Natural logarithm redirects here)
The natural logarithm is the logarithm to base e. That is, when e^x = y, ln y = x is called the natural logarithm.
Common logarithm
(Common logarithm redirects here)
In mathematics, the common logarithm is the logarithm with base 10. It was invented in the 17th century by the English mathematician Henry Briggs. The base is omitted and it is written log N.
See also
- e or Euler's number