Question

find the sum of the following geometric series
+5 -20 +80 -320 + ... -20 971 520

Answer 1

You can solve the given series using Sequences and series.

Answer 2

use geometric series formula

Answer 3

your q=-4 b1=5 and bn=-20971520

Answer 4

find n there and substitue to the formula s=...

Answer 5

search google for geometric sequence formulads

Answer 6

the nth term of the series is 5(-4)^(n-1)

number of terms in the sequence is 12

so sum of geometric series will be \[5 * \left( 1-4^{12}) \right)\div(1-4)\]