Question 367820
A child on a swing is given a big push. she travels 12 feet on the first back and forth swing, but only 5/6 as far on each successive swing. How far does she travel before the swing stops?
<pre>
This is an infinite geometric series.  Theoretically the swing never
stops, but we know it doesn't.  However we work it mathematically as though
it never stops, but eventually swings through such a small distance that it
is negligible.  The formula for an infinite geometric series:

{{{S[infinity]=a[1]/(1-r)}}}

where {{{a[1]=12}}}, {{{r=5/6}}}

{{{S[infinity]=12/(1-5/6)=12/(1/6)=12*(6/1)=72}}} feet.

Edwin</pre>