We continue with power series, takes us in a different,
		and very important, direction. Last time we explored using a
		workhorse of a "power series" explored in this section. 
	\[
	\sum_{k=0}^\infty x^k = \frac{1}{1-x}
	\]
	which is convergent when \(|x|<1\). 
	 Our materials for power series:
		
		
		-  Last time we were working out some examples from the text,
		in this PowerSeries.nb
		file (PowerSeries.pdf) -- from
		the text's section on Power series (Vol
		2, Sec 6.1: Power Series and Functions)
		
 -    (Power_series.nb)
 		
 -    (Power_series.pdf)