Base Change Formula of Log

This formula is employed when expressing a logarithm of a number with a particular base as a ratio of two logarithms, each with a different base than the original logarithm. This is a logarithmic characteristic. The formula is given as:

logba = logca / logcb 

or

logba . logcb = logca

Change of Base Formula

The change of base formula is a useful concept in mathematics. Especially when dealing with logarithms, It allows you to convert a logarithm from one base to another. Change of base formula in logarithm allows us to rewrite a logarithm with a different base. Instead of calculating the logarithm directly with the given base, we can use a different base and adjust the formula accordingly.

The significance of the change of Base Formula lies in its practical applications. It allows us to compute logarithms using calculators or computational tools that may only support logarithms with certain bases, typically base 10 (log10​) or natural logarithms (ln⁡). This formula is also useful in solving equations involving logarithms, simplifying expressions, and proving various mathematical identities.

Table of Content

  • Change of Base Formula
  • Base Change Formula of Log
  • Derivation of Change of Base Formula
  • Properties of Log Change of Base
  • Solved Questions using Change of Base Formula

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Change of Base Formula

The change of base formula is used to alter the base of a logarithm, as its name implies. The scientific calculator only has two buttons: log and ln, where the former represents a base 10 logarithm and the latter is used for a base e logarithm. But these buttons don’t calculate for values of bases other than 10 and e. This problem is resolved by changing the basic formula. It’s also utilized to solve a variety of logarithms difficulties....

Base Change Formula of Log

This formula is employed when expressing a logarithm of a number with a particular base as a ratio of two logarithms, each with a different base than the original logarithm. This is a logarithmic characteristic. The formula is given as:...

Derivation of Change of Base Formula

Below is the derivation of Change of Base Formula....

Properties of Log Change of Base

The rule of base change is a logarithmic property that enables the input of a logarithm with a base other than 10 into a calculator. The equation is: logd​c = log10​c​/log10​d The base change formula is useful for calculating logarithms on a calculator that only supports base 10. The base change formula can also help simplify certain logarithmic expressions. The base change formula is compatible with the natural logarithm, ln: log(b) = ln(b)/ln(a)​ . Most calculators provide the option to input the base of a logarithm. The formula is only applicable to logarithms with positive bases. Both the numerator and the denominator of the formula represent logarithms with the same base c....

Solved Questions using Change of Base Formula

Question 1: Evaluate log648 using the change of base formula....

Change of Base Formula – FAQs

How to use change of base formula?...