Question

PLEASE HELP! WILL MEDAL! Find the sum of the series.

Answer 1

\[\sum_{n=1}^{15} (2n+1)\]

Answer 2

there are a couple ways to do this

Answer 3

Okay I need the simplest way because I'm not good with this.

Answer 4

ok lets find the first term, which means replace \(n\) by \(1\)
what do you get?

Answer 5

3?

Answer 6

if that is confusing too, let me know and i will show you
lol no not "3?" just "3"

Answer 7

I know it is just 3 I was asking if 3 was right.

Answer 8

yeah \(2\times 1+1=3\)
ok now the top number is 15 so lets find the 15th term
replace \(n\) by \(15\) and see what you get

Answer 9

31

Answer 10

ok good
now there are 15 terms all together
one formula you can use is
\[\huge \frac{n}{2}\left(a_1+a_n\right )\]

Answer 11

you computed \(a_1=3,a_{15}=31\) and in this case \(n=15\)

Answer 12

so do this
\[\frac{15}{2}(3+31)\]

Answer 13

15/2(33)

Answer 14

add first, divide by 2 then multiply by 15

Answer 15

you got that?

Answer 16

I meant 34 my number buttons are acting up and no. I was just stating the equation.

Answer 17

ok so now divide 34 by 2
then multiply the result by 15

Answer 18

255

Answer 19

you found the sount

Answer 20

sound
bingo
yes
good work

Answer 21

Thank you for your help!

Answer 22

yw