For \(a>0,\ a\ne1,\ M>0\) and real \(r\):
\(\log_a(M^r)=r\log_a M\)
Examples
| Expression | Simplified form |
|---|---|
| \(\log_2(5^x)\) | |
| \(\log_3\sqrt{2}\) | |
| \(\lg\sqrt[3]{x},\ x>0\) |
Watch the brackets
For \(x>0\): \(\lg(2x^3)=\lg2+3\lg x\), whereas \(\lg((2x)^3)=3\lg(2x)\).
\((\log_a x)^3\) is the cube of the logarithm; the power law does not apply.
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