Question

Find the sum of the first 20 terms of the series ...

Answer 1

1 + 3 + 9 + 27+...

Answer 2

@amistre64 @surjithayer

Answer 3

define a rule for the sequnce

Answer 4

looks like adding the multiples of 3

Answer 5

powers of 3 maybe?

Answer 6

it's a geometric series with a common ratio of 3.

Answer 7

so its geometric ...\[S_n=\frac{1-r^n}{1-r}\]

Answer 8

did I do this correctly? here is what I have \[\frac{ 1(1-(3)^{20}) }{ 1-3}\]

Answer 9

20 terms is hardly infinite .... maybe if your lie 7 but not really :)

Answer 10

yeah, thats fine

Answer 11

okay and the answer is 1,743,392,200?

Answer 12

my spider senses tell me .... sure maybe.

Answer 13

looks good to me yes

Answer 14

haha thanks spider-man!

Answer 15

everyone gets one ... tell them peter! lol

Answer 16

☻

Answer 17

im spose to be at an awards ceremony but have no idea where its at :/

Answer 18

for what?

Answer 19

it was academic excellence day at my college and i presented my senior project

Answer 20

oh that's cool but sucks at the same time haha , well thanks for the help! good luck finding it.