Question

series question

Answer 1

http://gyazo.com/11d360e31e398a1174844702893f4562

Answer 2

how do i start?

Answer 3

Plug in 1 for n, for next term plug in 2 for n

And so forth.
Good?

Answer 4

\[a_n = (3-1(2^{-1}) + (3-2(2^{-2}) +...+ (3-n(2^{-n})\] thats all?

Answer 5

Nothing more, and then find the sum of the series.

Answer 6

I mean you put in pluses already, but there is an easier way to find the sum of the series.
Write out the series and I'll show, OK?

Answer 7

is it a geometric series?

Answer 8

Write it out, and will see.

Answer 9

(2.5 +2.5 +2.625 + ...)

Answer 10

Can you please put it in fractions?

Answer 11

( 5/2 + 5/2 + 21/8 +...)

Answer 12

The series is infinite, so if the terms are increasing you can't find the sum

Answer 13

Are they?

Answer 14

i have no idea

Answer 15

OK, looking at the series, your exponents are becoming negative and therefore the bigger the n the bigger the fraction is going to be formed, Now look at the problem closely keeping what I told you in mind. Would you agree that the bigger it is going to get the more it is going to approach 3? (they are not asking for exact sum, b/c it doesn't exist in infinite series.

Answer 16

@mathsnerd101, do you see why is the series ('s sum) going to approach 3 the bigger the series gets?

Answer 17

So the answer is 3.