Solution 3.3:3b
From Förberedande kurs i matematik 1
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| - | {{  | + | Because we are working with   | 
| - | <  | + | <math>\log _{9}</math>, we express   | 
| - | {{  | + | <math>{1}/{3}\;</math>  | 
| + | as a power of  | ||
| + | <math>\text{9}</math>,  | ||
| + | |||
| + | |||
| + | <math>\frac{1}{3}=\frac{1}{\sqrt{9}}=\frac{1}{9^{{1}/{2}\;}}=9^{-{1}/{2}\;}</math>  | ||
| + | |||
| + | |||
| + | Using the logarithm laws, we get  | ||
| + | |||
| + | |||
| + | <math>\log _{9}\frac{1}{3}=\log _{9}9^{-{1}/{2}\;}=-\frac{1}{2}\centerdot \log _{9}9=-\frac{1}{2}\centerdot 1=-\frac{1}{2}.</math>  | ||
Revision as of 14:06, 25 September 2008
Because we are working with \displaystyle \log _{9}, we express \displaystyle {1}/{3}\; as a power of \displaystyle \text{9},
\displaystyle \frac{1}{3}=\frac{1}{\sqrt{9}}=\frac{1}{9^{{1}/{2}\;}}=9^{-{1}/{2}\;}
Using the logarithm laws, we get
\displaystyle \log _{9}\frac{1}{3}=\log _{9}9^{-{1}/{2}\;}=-\frac{1}{2}\centerdot \log _{9}9=-\frac{1}{2}\centerdot 1=-\frac{1}{2}.
