SOLUTION: Sequence: 3, -6, 12, -24, 48,..., find S(sub 20). If S(sub 0)= 3. Then find the sum through S(sub 20). Thank you so much for your time, and everything in helping me understand

Algebra ->  Sequences-and-series -> SOLUTION: Sequence: 3, -6, 12, -24, 48,..., find S(sub 20). If S(sub 0)= 3. Then find the sum through S(sub 20). Thank you so much for your time, and everything in helping me understand       Log On


   



Question 634668: Sequence: 3, -6, 12, -24, 48,..., find S(sub 20). If S(sub 0)= 3. Then find the sum through S(sub 20).
Thank you so much for your time, and everything in helping me understand this problem! Thank you!

Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 
Hi,
3, -6, 12, -24, 48,..., Geometric Series, r = -2
S%5Bn%5D+=+a%5B1%5D%28%281-r%5En%29%2F%281-r%29%29
S%5B20%5D+=+3%28%281-%28-2%29%5En%29%2F%283%29%29+=+-1048575