Question 1122507
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find the sum of each of the following G.p's:
(a) 6,12, 24, ... to 10 terms 
(b) 1,-0.5, 0.25, 0.125 ... to 20 terms.
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What is presented in part  (b),  is not a geometric progression.


It is a rude  MISTAKE  to call it a  " geometric progression ",  while it is not.