Question

The population of a type of local dragonfly can be found using an infinite geometric series where a1 = 65 and the common ratio is 1/6. Find the sum of this infinite series that will be the upper limit of this population.

78

28

11

32

Answer 1

Do you know the formula?

Answer 2

kind of...

Answer 3

Formula for..?

Answer 4

\[\sum_{i=?}^{\infty}.. \]
i think that is it..

Answer 5

this is alg. 2 sigma notation....

Answer 6

http://www.examsolutions.net/maths-revision/core-maths/sequences-series/geometric/sum-to-infinity/infinity_sum.gif

Answer 7

... i dont think that is correct....

Answer 8

Yes. You can use this formula too.

Answer 9

... well can u help me work through it?

Answer 10

Sure.

Answer 11

So the formula is:
\[\Large S_{\infty} = \frac{a}{1-r}\]
a is the first term. r is the ratio.
Substitute your values.

Answer 12

\[s \infty=0.16/1-r\]

Answer 13

a1 = 65
r = 1/6

Answer 14

my bad, thats what i meant to put.. ive had a long day..

Answer 15

No problem.

Answer 16

well can u help me with the answer..? please

Answer 17

Give it a try.

Answer 18

i got 78? am i right?

Answer 19

@saifoo.khan

Answer 20

Yes. You're correct.