\section{Logarithms} \problem{} Evaluate the following by hand: \begin{enumerate} \item $\log_{10}{(1000)}$ \vfill \item $\log_2{(64)}$ \vfill \item $\log_2{(\frac{1}{4})}$ \vfill \item $\log_x{(x)}$ for any $x$ \vfill \item $log_x{(1)}$ for any $x$ \vfill \end{enumerate} \problem{} Prove the following: \begin{enumerate}[itemsep=2mm] \item $\log_b{(b^x)} = x$ \vfill \item $b^{\log_b{x}} = x$ \vfill \item $\log_b{(xy)} = \log_b{(x)} + \log_b{(y)}$ \vfill \item $\log_b{(\frac{x}{y})} = \log_b{(x)} - \log_b{(y)}$ \vfill \item $\log_b{(x^y)} = y \log_b{(x)}$ \vfill \end{enumerate} \begin{instructornote} A good intro to the following sections is the linear slide rule: \note{Note that these rules start at 0.} \begin{center} \begin{tikzpicture}[scale=0.6] \linearscale{2}{1}{} \linearscale{0}{0}{} \slideruleind {5} {1} {2 + 3 = 5} \end{tikzpicture} \end{center} Take two linear rules, offset one, and you add. Do the same with a log scale, and you multiply! \\ \linehack{} After assembling the paper slide rule, you can make a visor with some transparent tape. Wrap a strip around the slide rule, sticky side out, and stick it to itself to form a ring. Cover the sticky side with another layer of tape, and trim the edges to make them straight. Use the edge of the visor to read your slide rule! \end{instructornote} \pagebreak