LOGARITHMS
(Prepared by P. Sivadas Master)
The Scottish mathematician John Napier invented logarithms. He designed the method of logarithms to make mathematical calculations very easy. Logarithms were very widely used before calculators were invented.
Definition:
Logarithm of a number to a given base is the power to which the base must be raised to equal the number.
If N = bx , then x is said to be the logarithm of N, to the base b. It is written as
Log b N = x
(Read as log N to the base b equal to x)
Types of logarithms
Logarithms are of two types - Natural Logarithms and Common Logarithms. Logarithms with base ‘e’, where e = 2.71828, is known as Natural Logarithms. Logarithms with base 10 are known as Common Logarithms.
Natural logarithm of number = 2.303 x Common logarithm of that number