Question 34410
a geometric sequence is one that has a common factor (ie a multiplier) between terms. Just looking at the sequence... start at 1. What do we multiply it by to get to next number, 2. Answer is 2... r=2.


If you have a more awkward sequence, then divide one term by the previous one: 8/4 is 2. 4/2 is 2. 2/1 is 2 etc.


24th term:
1st term is a
2nd term is ar
3rd term is ar^2
4th term is ar^3
...
24th term is ar^23


So, {{{ ar^23 }}}
{{{ (1)(2)^23 }}}
{{{ 2^23 }}}
work it out yourself :-)


sum of 10 = {{{ (a(r^(n)-1))/(r-1) }}}
sum of 10 = {{{ ((1)(2^(10)-1))/(2-1) }}}
sum of 10 = {{{ (2^(10)-1)/(1) }}}
sum of 10 = {{{ 1024-1 }}}
sum of 10 = 1023


jon.