$6\mathrm{.}28($a$)$ Use the R code

L $=0$

for$($i in $1$:$($n$-1))\{$

L $=$ L $+$ sqrt$(($x$[$i$+1]-$ x$[$i$])2+($y$[$i$+1]-$ y$[$i$])2)$

$\}$

L

to compute the approximate length of the curve in Fig. $6\mathrm{.}17($a$).$

$($b$)$ Compare with this length with the length computed in the previous