The sum of the first [tex]n[/tex] terms of a geometric sequence is given by:
[tex]S_{n}=\frac{a_{1}(1-r^{n})}{1-2}[/tex]
Using the known values: [tex]S_{8}=\frac{6(1-0.5^{8})}{1-0.5}[/tex] [tex]S_{8}=\frac{6(1-0.00390625)}{0.5}[/tex] [tex]S_{8}=\frac{6(0.99609375)}{0.5}[/tex] [tex]S_{8}=\frac{5.9765625}{0.5}[/tex] [tex]S_{8}=11.953125[/tex]
