Question

What is the sum of a 6-term geometric sequence if the first term is 11, the last term is –11,264 and the common ratio is –4?

Answer 1

Geometric Sum `S_n=[a_1 - a_(n+1)]/(1-r)`

Explanation:

For this problem ...

`a_1=11`

`a_(6+1)=-11264xx-4=45056`

Geometric Sum `S_6=[11 - 45056]/(1-(-4))=-9009`

Hope that helped