Question

Find the sum of the series 12∈n-1(2n+1)?

Answer 1

@Ashleyisakitty Can you re-write that in LATex/equation editor?

Answer 2

\[\sum_{n-1}^{12}(2n+1)\]

Answer 3

any ideas?

Answer 4

You start at n = -1... and keep going until you get to 12.

-1 + 1 + 3 + 5 + 7 + 9 + ....+ n11+ n12

Answer 5

*starting where you left off*
11+13+15+17+19+21.

What do i do next?

Answer 6

add them on your calculator.

Answer 7

120

Answer 8

That is the sum of the terms starting at n = -1 to n = 12.

Answer 9

these are what i have to chose from

Answer 10

Alright Just making Sure that n =-1 or is it 1?

Answer 11

Under the E thingy? Yes it is n-1

Answer 12

if youre talking at the end it is +1

Answer 13

Here is the summation of an arithmetic sequence.\[Sn = \frac{ n }{ 2 } [2a1+(n-1)d]\]

Answer 14

You were correct the answer was 144.