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%$Header$ |
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\chapter[Solutions: \ccfrzeroxrefcomma{}Chapter \ref{ccfr0}] |
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{Solutions: \ccfrzeroxrefcomma{}Chapter \ref{ccfr0}, \ccfrzerolongtitle{}} |
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\label{ccfs0} |
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\vworkexercisechapterheader{} |
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\begin{vworkexercisesolution}{\ref{exe:cfr0:sexe0:a01}} |
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Placeholder. |
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\end{vworkexercisesolution} |
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\vworkexerciseseparator |
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\begin{vworkexercisesolution}{\ref{exe:cfr0:sexe0:b01}} |
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Note that $1.609344 > 255/255$ (i.e. beyond the ``corner point'' |
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in the sense suggested by Fig. \cfryzeroxrefhyphen{}\ref{fig:cfry0:ili0:00}), |
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so it is necessary to find |
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the Farey neighbors of $1.609344^{-1}$ in $F_{255}$ |
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(Algorithm \ccfrzeroxrefhyphen{}\ref{alg:ccfr0:scba0:cfenclosingneighborsfab}), |
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and then invert and re-order the results. |
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Table \ref{tbl:ccfs0:exe:cfr0:sexe0:b01:01} |
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shows the application of |
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Algorithm \ccfrzeroxrefhyphen{}\ref{alg:ccfr0:scrn0:akgenalg} |
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to form the continued fraction partial quotients and |
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convergents of $1.609344^{-1}$ = 1,000,000/1,609,344. |
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\begin{table} |
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\caption{Continued Fraction Partial Quotients And Convergents Of $1.609344^{-1}$, |
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The Reciprocal Of The Conversion Factor From Miles |
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To Kilometers (Solution To Exercise \ccfrzeroxrefhyphen{}\ref{exe:cfr0:sexe0:b01})} |
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\label{tbl:ccfs0:exe:cfr0:sexe0:b01:01} |
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\begin{center} |
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\begin{tabular}{|c|c|c|c|c|c|c|} |
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\hline |
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\small{Index} & \small{Dividend} & \small{Divisor} & $a_k$ & \small{Remainder} & $p_k$ & $q_k$ \\ |
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\small{(k)} & & & & & & \\ |
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\hline |
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\hline |
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\small{-1} & \small{N/A} & \small{1,000,000} & \small{N/A} & \small{1,609,344} & \small{1} & \small{0} \\ |
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\hline |
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\small{0} & \small{1,000,000} & \small{1,609,344} & \small{0} & \small{1,000,000} & \small{0} & \small{1} \\ |
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\hline |
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\small{1} & \small{1,609,344} & \small{1,000,000} & \small{1} & \small{609,344} & \small{1} & \small{1} \\ |
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\hline |
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\small{2} & \small{1,000,000} & \small{609,344} & \small{1} & \small{390,656} & \small{1} & \small{2} \\ |
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\hline |
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\small{3} & \small{609,344} & \small{390,656} & \small{1} & \small{218,688} & \small{2} & \small{3} \\ |
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\hline |
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\small{4} & \small{390,656} & \small{218,688} & \small{1} & \small{171,968} & \small{3} & \small{5} \\ |
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\hline |
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\small{5} & \small{218,688} & \small{171,968} & \small{1} & \small{46,720} & \small{5} & \small{8} \\ |
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\hline |
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\small{6} & \small{171,968} & \small{46,720} & \small{3} & \small{31,808} & \small{18} & \small{29} \\ |
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\hline |
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\small{7} & \small{46,720} & \small{31,808} & \small{1} & \small{14,912} & \small{23} & \small{37} \\ |
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\hline |
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\small{8} & \small{31,808} & \small{14,912} & \small{2} & \small{1,984} & \small{64} & \small{103} \\ |
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\hline |
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\small{9} & \small{14,912} & \small{1,984} & \small{7} & \small{1,024} & \small{471} & \small{758} \\ |
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\hline |
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\small{10} & \small{1,984} & \small{1,024} & \small{1} & \small{960} & \small{535} & \small{861} \\ |
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\hline |
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\small{11} & \small{1,024} & \small{960} & \small{1} & \small{64} & \small{1,006} & \small{1,619} \\ |
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\hline |
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\small{12} & \small{960} & \small{64} & \small{15} & \small{0} & \small{15,625} & \small{25,146} \\ |
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\hline |
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\end{tabular} |
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\end{center} |
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\end{table} |
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From the table, the highest-ordered convergent with a denominator not greater |
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than 255 is 64/103. Applying |
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Theorem \ccfrzeroxrefhyphen{}\ref{thm:ccfr0:scba0:convergentbetterappthanlesserdenominator} |
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yields 151/243 as the other neighbor to |
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$1.609344^{-1}$ in $F_{255}$. Inverting and ordering these |
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fractions yields |
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\begin{equation} |
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\frac{243}{151} < 1.609344 < \frac{103}{64}. |
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\end{equation} |
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Either rational approximation is quite good, but 103/64 is closer |
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to 1.609344 than 243/151, and so we choose 103/64 as the best |
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rational approximation under the constraints. |
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\end{vworkexercisesolution} |
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\vworkexerciseseparator |
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\begin{vworkexercisesolution}{\ref{exe:cfr0:sexe0:b02}} |
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To find the best rational approximation to 1.609344 with |
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a numerator and denominator no larger than 65,535, first consider the |
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possibility that 1.609344 is already a rational number that can |
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be expressed under these constraints. Examining the final |
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convergent\footnote{For a rational number, the final convergent |
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is the rational number in lowest terms. This is established |
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by Theorem \ccfrzeroxrefhyphen{}\ref{thm:ccfr0:scnv0:evenslessthanoddsgreaterthan}.} |
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of Table \ref{tbl:ccfs0:exe:cfr0:sexe0:b01:01} verifies |
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that 1.609344 = 25,146/15,625. Thus, the best rational |
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approximation under |
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the constraints is 25,146/15,625, which is precisely equal to the |
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number to be approximated. |
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\end{vworkexercisesolution} |
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\vworkexercisechapterfooter |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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\vfill |
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\noindent\begin{figure}[!b] |
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\noindent\rule[-0.25in]{\textwidth}{1pt} |
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\begin{tiny} |
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\begin{verbatim} |
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dashley |
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$HeadURL$ |
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$Revision$ |
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$Date$ |
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$Author$ |
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dashley |
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\end{verbatim} |
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\end{tiny} |
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\noindent\rule[0.25in]{\textwidth}{1pt} |
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\end{figure} |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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% |
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%End of file C_CFS0.TEX |