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Do Now:. Algebra II. 6.3 Logarithms and logarithmic functions. Logarithms. We know that 2 2 = 4 and 2 3 = 8. What value of x does 2 x = 6? Mathematicians define this x-value using a logarithm and write x = log 2 6. Definition of Logarithm with base b.
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Algebra II 6.3 Logarithms and logarithmic functions
Logarithms We know that 22 = 4 and 23 = 8. What value of x does 2x = 6? Mathematicians define this x-value using a logarithm and write x = log26.
Definition of Logarithm with base b Let b and y be positive real numbers with b ≠ 1. The logarithm of y with base b is denoted by logby and is defined as: The expression logby is read as “log base b of y”
What’s important? This definition tells us that the following equations are equivalent. The first is logarithmic form, and the second is exponential form.
Important Numbers 1 and 2 in the last example illustrate two special logarithm values that we should learn to recognize before we start graphing.
Evaluating Common and Natural Log Evaluate using a calculator. Round your answer to three decimal places (a) log 8 (b) ln 0.3