Use the properties of geometric series to find the sum of the series. For what values of the variable does the series converge to this sum? 2+28x+ 112x² +448x³ + ... sum= domain = (Give your domain as an interval or comma separated list of intervals; for example, to enter the region X < -1 and 2 < x leq 3, enter (-infinity,-1), (2,3].)