Logarithm

Definition of Logarithm

• For any , if , then logarithm of ‘r’ to base ‘q’ is ‘p’ and it can be written as . Log is the abbreviation for Logarithm.

Examples of Logarithm

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More about Logarithm

• Common Logarithms: Logarithms that use 10 as the base are called common logarithms.
• Natural Logarithms: Logarithms with base ‘e’ are called common logarithms and it is written as y = ln x.
• Logarithmic Function: The inverse of exponential function is known as a logarithmic function.
• Logarithmic Equation: An equation containing one or more logarithms is called a logarithmic equation.

Solved Example on Logarithm

Which one of the following expresses  in logarithmic form?

Choices:

A.

B.

C.

D.

Correct Answer: C

Solution:

Step 1: For any , if , then logarithm of ‘r’ to base ‘q’ is ‘p’ and it can be written as .

Step2: From the definition, can be expressed in the logarithmic form as  .    

Related Terms for Logarithm

• Base

Additional Links for Logarithm

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