Question 880060
<pre>
To find r we divide {{{matrix(1,2,2nd,term)/matrix(1,2,1st,term)}}}{{{""=""}}}{{{12/8}}}{{{""=""}}}{{{3/2}}}

As a check, also divide {{{matrix(1,2,3rd,term)/matrix(1,2,2nd,term)}}}{{{""=""}}}{{{18/12}}}{{{""=""}}}{{{3/2}}}

and

{{{matrix(1,2,4th,term)/matrix(1,2,3rd,term)}}}{{{""=""}}}{{{27/18}}}{{{""=""}}}{{{3/2}}}

So {{{r}}}{{{""=""}}}{{{3/2}}}

Formula for the sum of the first n terms of a geometric series:

{{{S[n]}}}{{{""=""}}}{{{(a[1](r^n-1))/(r-1)}}}

where {{{n}}}{{{""=""}}}{{{45}}} and {{{r}}}{{{""=""}}}{{{3/2}}}, {{{a[1]}}}{{{""=""}}}{{{8}}}

{{{S[45]}}}{{{""=""}}}{{{(8((3/2)^45-1))/((3/2)-1)}}}{{{""=""}}}{{{1343465861}}}

Edwin</pre>