Hi,

this "sum(1/(1+x)^t, t=1..infinity)" is (in my opionon) one of the most standard infinity summation and has the closed form 1/x. 
i used maple 18 and it was executed and i got the closed form 1/x.

with maple 2018 i get the non executed form, also the same inert form as "Sum(1/(1+x)^t, t=1..infinity)".

if i try "sum(1/(1+2)^t, t=1..infinity)" i get 1/2 as result.

why does the version above not working? any ideas?

thank you.