Question

Please help
1 - 1/4 + 1/16 – 1/64 + 1/256 – 1/1024 + 1/4096 Find the sum of the finite geometric series

Answer 1

so unnecessary to spam...

Answer 2

sorry

Answer 3

first define the geometric sequence.

Answer 4

its the bottoms they all mutiply by themselves

Answer 5

by x4

Answer 6

not just 4, by negative 4 since it changes sign, correct?

Answer 7

see thats where I get confused

Answer 8

So you start with 1. You multiply by (-1/4) you get (-1/4)

Answer 9

then you multiply again my -1/4

Answer 10

so you get (1/16) since the negative multiplied by negative is a positive, correct?

Answer 11

Yes

Answer 12

So that, is what we call the "r" term in a geometric series (ie. the number we always multiply with)

Answer 13

ok

Answer 14

do you know the sum of a geometric sequence, the formula?

Answer 15

so to find the sum? how do I use that with the figures

Answer 16

No

Answer 17

do u mean like s with the little n

Answer 18

hmm... actually since your question is asking how to find the sum of the ***finite*** geometric series, you could probably add them all together

Answer 19

so Id get 7/ over and bottom total added?

Answer 20

Try again, in order to add fractions they need a common denominator...

Answer 21

7/ 4096...OR DO YOU MEAN LIKE 28/4096

Answer 22

... it's actually 3277/4096

Answer 23

http://www.wolframalpha.com/input/?i=1+-+1%2F4+%2B+1%2F16+%E2%80%93+1%2F64+%2B+1%2F256+%E2%80%93+1%2F1024+%2B+1%2F4096

Answer 24

oh...wow I like the page I will have to check that out.. thanks

Answer 25

you could have also used the S n thing as well to figure it out. Probably easier.