Answer:
[tex]S_{8}[/tex] = [tex]-255)[/tex].
Step-by-step explanation:
Given : geometric sequence: 3, –6, 12, –24.
To find : Find s8 for the following geometric .
Solution : We have given geometric sequence: 3, –6, 12, –24.
Where, first term = 3, common ration : [tex]\frac{-6}{3}[/tex] = -2.
Formula used : [tex]a(\frac{1-r^{n}}{1-r} )[/tex]
Where, a = first term , r = common ratio.
[tex]S_{8}[/tex] = [tex]3(\frac{1-(-2)^{8}}{1-(-2)} )[/tex].
[tex]S_{8}[/tex] = [tex]3(\frac{1- 256}{1+2} )[/tex].
[tex]S_{8}[/tex] = [tex]3(\frac{-255}{3} )[/tex].
[tex]S_{8}[/tex] = [tex]3 * (85)[/tex].
[tex]S_{8}[/tex] = [tex]-255)[/tex].
Therefore, [tex]S_{8}[/tex] = [tex]-255)[/tex].
