Exercise 3.2.2
Prove equation (3.16)
$$ a^{\log_bc} = c^{\log_ba} $$
$$ \begin{aligned} a^{\log_bc} = a^{\frac{\log_ac}{\log_ab}} = \big(a^{\log_ac})^\frac{1}{\log_ab} = c^{\log_ba} \end{aligned} $$
Prove equation (3.16)
$$ a^{\log_bc} = c^{\log_ba} $$
$$ \begin{aligned} a^{\log_bc} = a^{\frac{\log_ac}{\log_ab}} = \big(a^{\log_ac})^\frac{1}{\log_ab} = c^{\log_ba} \end{aligned} $$