In Try This 1 you may have determined the following patterns. They are called the laws of logarithms.
LAWS OF LOGARITHMS |
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Law of Logarithms |
Law Expressed Mathematically |
Comparison Between Law of Logarithm and Law of Powers |
Product Law of Logarithms |
logb (M × N) = logb M + logb N |
(bm)(bn) = bm+n
logb (M × N) = logb M + logb N
Note that multiplying terms in a logarithm or powers is equal to the sum of the logarithms or exponents. |
Quotient Law of Logarithms |
Note that dividing terms in a logarithm or powers is equal to the difference between the logarithms or exponents. |
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Power Law of Logarithms |
logb (Mn) = nlogb M |
logb (Mn) = nlogb M
Note that a power in a logarithm or a power to a power is equal to the product of the power and the logarithm or the exponents of the power. |
Open Properties of Logarithms to see how the laws of logarithms can be derived. Choose the Tutorial button (), and then select The Product Law of Logarithms. Work your way through the activities.