A logarithm represents the exponent required to produce a positive number from a specified positive base: precisely when , with , , and . This inverse relationship enables interpretation and solution of exponential equations, including integer, fractional, and negative exponents, while excluding complex logarithms and more advanced properties or applications beyond real-number relationships.
A logarithm tells you the exponent needed to produce a number:
Here, is the positive base, is the positive number inside the logarithm, and is the exponent.
Example: Find .
Let
Use the definition of a logarithm to rewrite this as an exponential equation:
Rewrite as a power of :
Therefore,
Since the bases are the same, the exponents must be equal:
So,
This means that the exponent required to produce from base is , because
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