The document defines logarithms by showing their exponential and logarithmic forms. It gives examples of writing expressions in both exponential and logarithmic form, as well as evaluating logarithmic expressions and solving logarithmic equations. The key points are that logarithms relate the exponent to the base in exponential form and logarithmic form allows solving for the exponent.

1. 8.4 defn of logarithms.notebook February 01, 2013
8.4 Definition of Logarithms
Exponential Form Logarithmic Form
23 = 8 log28 = 3
24 = 16 log216 = 4
20 = 1 log 1 = 0
2
2­1 = 1/2
log21/2 = ­1
2k = N log N = k
2
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2. 8.4 defn of logarithms.notebook February 01, 2013
Write the equation in exponential form.
1. log636 = 2 2. log22 = 1 3. log10(0.001) = ­3
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3. 8.4 defn of logarithms.notebook February 01, 2013
Write each equation in logarithmic form.
4. 60 = 1 5. 8­2/3 = 1/4 6. 53/2 = 5√5
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4. 8.4 defn of logarithms.notebook February 01, 2013
Evaluate the expression.
log27
7. 8. 9. 2
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5. 8.4 defn of logarithms.notebook February 01, 2013
Solve each equation.
10. log4x = 3 11. logx81 = 4
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