Question 887117
<pre>
{{{1/2}}} does work!

You are talking about {{{sum((1/2^n),matrix(1,3,"","",n=1),matrix(1,4,"","","",infinity))}}}{{{""=""}}}{{{1/2^1+1/2^2+1/2^3+""*""*""*""}}}

Certainly the common ratio is {{{r=1/2}}} because any term after the first
divided by the preceding term is always {{{1/2}}}

{{{S[infinity]}}}{{{""=""}}}{{{a[1]/(1-r)}}}, with {{{a[1]=1/2}}}, {{{r=1/2}}}

{{{S[infinity]}}}{{{""=""}}}{{{(1/2)/(1-expr(1/2))}}}{{{""=""}}}{{{(1/2)/(1/2)}}}{{{""=""}}}{{{1}}}.

Edwin</pre>