Infinite Series Problem

[Terje Vallestad]

(01-07-2016 11:32 PM)chazzs Wrote:  So far none of the suggestions have worked, neither with the summation sign, nor the sum command. I think the problem lies with it being an alternating series and the parsing of the parentheses. The prime seems to be ignoring the parentheses around the base (-0.75)^k. Non alternating series and partial sums seem to work, but not an infinite alternating series. Still not sure what is actually happening though. Seems a little random on what is evaluated and what is no.

If you enter Σ(-9*(-3/4)^(k-1),k,1,∞) in (algebraic notation in) CAS you should get the desired result. You can also use textbook and the template and get the same result. The multiplication must be explicit between -9 and (-3/4), and as seems to be the case with most CAS functions the Angle Measure setting must be Radians.

Hope this helps

Cheers, Terje