Can we prove $$a^{\log_bn} = n^{\log_ba}?$$ I forget how to prove this theorem. I picked up one numbers for test, and they worked.
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Take the log to the base $b$ of both sides. |
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$a^{\log_b{n}}=n^{\log_b{a}}$/$\cdot$ $\log_a$ $\log_a a^{\log_b{n}}=\log_a n^{\log_b{a}}$ $\log_b{n}=\log_b{a} \log_a n$ $\log_b{n}=\frac{\log a}{\log b}\cdot\frac{\log n}{\log a}$ $\log_b{n}=\frac{\log n}{\log b}$ |
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$$a^{\log_b n}=n^{\log_n a \log_b n}=n^{\log_b a},\quad \text{using}\quad\log_n a=\frac{\log_b a}{\log_b n}\quad \text{and}\quad\log_n a=\frac{\log_b a}{\log_b n}.$$ |
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