7.1.3 Logarithmic Functions Key Objectives • Write, evaluate, and graph logarithmic functions. Key Terms • A logarithm is the exponent that a specified base must be raised to in order to get a certain value. • A common logarithm is a logarithm whose base is 10, denoted log 10 or just log. • A logarithmic function is a function of the form f ( x ) = log b x , where b ≠ 1 and b > 0, which is the inverse of the exponential function f ( x ) = bx . The logarithmic equation log b a = x is read as “log base b of a is x .” A logarithmic equation of the form log b a = x (where b > 0 and b ≠ 1) can be written in exponential form as b x = a .
Example 1 Converting from Exponential to Logarithmic Form
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