\magnification 2200 \vsize 10truein \voffset -0.4truein \nopagenumbers \parskip 8pt \parindent 0 pt \def\u{\vskip 3.3in} \def\v{\vskip 2.2in} \def\w{\vskip 10pt} \def\z{\vskip 1.2in} $a^x a^y = a^{x + y}$ \hfill ${a^x \over a^y} = a^{x - y}$ $(a^x)^y = a^{xy}$ \hfill $(ab)^x = a^x b^x$ Ex: $2^8 5^6$ = Suppose $f(x) = a^x$ \vskip -10pt ~~~~~~~~~~~~$y = a^x$ Find $f^{-1}$ ~~~~~~Switch $x$ and $y$: $a^y = x$ ~~~~~~$log_a x = y$ iff $a^y = x$ $f^{-1}(f(x)) =$ $f(f^{-1} (x)) =$ $log_a x + log_a y = log_a (xy)$ $log_a x - log_a y = log_a ({x \over y})$ $log_a x^r = r log_a (x)$ $log_a a =$ \hfil $log_a 1 =$ \hfil $log_a 0 =$ \hfil Defn: $ln(x) = log_e x$ $log_a x = { ln(x) \over ln(a)}$ Note: $log_a x + log_a y \not= log_a (x + y) $ \end