Answer:
- 819
Step-by-step explanation:
The sum to n terms of a geometric series is
[tex]S_{n}[/tex] = [tex]\frac{a(r^n-1)}{r-1}[/tex]
where a is the first term and r the common ratio
Here a = 1 and r = - 4 ÷ 1 = - 4, thus
[tex]S_{6}[/tex] = [tex]\frac{1((-4)^6-1)}{-4-1}[/tex] = [tex]\frac{4096-1}{-5}[/tex] = [tex]\frac{4095}{-5}[/tex] = - 819
Answer:
-819
Step-by-step explanation:
This is Geometric series with first term as '1' and a common ratio of '-4' (-4÷1 = -4)
At n=5, the term is (-64×-4) = 256
At n=6, the term is (256×-4) = -1024
1-4+16-64+257-1024 = -819
