Logarithms

(a) Evaluate log₁₀ 10000
(b) Evaluate log₁₀ (-10000)

Use the index to log process

\[ \begin{align} 10000 &= 10^4 \\ \log_{10} 10000 &= \log_{10} 10^4 \\ &= 4 \end{align}\ \]

The log of a negative number is not defined

\[ \begin{align} \log_{10} (-10000) &= \text{not defined} \end{align}\ \]

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How do you evaluate the log of a number?

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