## Functions Modeling Change: A Preparation for Calculus, 5th Edition

$0$
Start with the innermost argument, $\log 10$. Since $\log 10^a=a$ and $10=10^1$, $\log10=\log10^1=1$. Therefore, $\log(\log 10)=\log(1)$ Since $1=10^{0}$, $$\log(\log 10)=\log(10^0)=0$$