Solution 3.3:6b

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The logarithm \displaystyle \lg 46 satisfies the relation

\displaystyle 10^{\lg 46} = 46

and taking the natural logarithm of both sides, we obtain

\displaystyle \ln 10^{\lg 46 } = \ln 46\,\textrm{.}

If we use the logarithm law, \displaystyle \lg a^b = b\cdot\lg a, on the left-hand side, the equality becomes

\displaystyle \lg 46\cdot\ln 10 = \ln 46\,\textrm{.}

This shows that

\displaystyle \lg 46 = \frac{\ln 46}{\ln 10} = \frac{3\textrm{.}828641\,\ldots}{2\textrm{.}302585\,\ldots} = 1\textrm{.}6627578\,\ldots

and the answer is 1.663.


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