Question

what does this mean??
i dont know this sign.

Answer 1

help help

Answer 2

it means sum it up

Answer 3

how do i solve it.

Answer 4

http://images.tutorvista.com/cms/images/39/sigma-notation-calculator.PNG

Answer 5

@jdoe0001 THANK YOU.

Answer 6

@jdoe0001 wait, though.
im still confused..

Answer 7

what do i do with the infinity sign?

Answer 8

in the exerices it shows the infinity sign, however it's asking for the "9TH partial sum"
so the 1st 9-terms SUMMED UP together

Answer 9

this doesnt make sense.

Answer 10

heheh

Answer 11

one sec

Answer 12

what are the 9 terms? where do i get them from...what

Answer 13

\(\large{ \Sigma_{{\color{red}{ i}}=2}^9\quad 3{\color{red}{ i}}-4\implies
\begin{cases}
1st&3({\color{red}{ 2}})-4+\\
2nd&3({\color{red}{ 3}})-4+\\
3rd&3({\color{red}{ 4}})-4+\\
4th&3({\color{red}{ 5}})-4+\\
5th&3({\color{red}{ 6}})-4+\\
6th&3({\color{red}{ 7}})-4+\\
7th&3({\color{red}{ 8}})-4+\\
8th&3({\color{red}{ 9}})-4+\\
9th&3({\color{red}{ 10}})-4
\end{cases} }\)

Answer 14

okay so i have to add all of those together and that is my answer?

Answer 15

well.. there are 9 terms, beginning with i=2.... so the "sigma notation" should really be \(\Large \bf \Sigma_{{\color{red}{ i}}=2}^{10}\quad 3{\color{red}{ i}}-4\)

Answer 16

yes

Answer 17

what are the Plus signs at the end of it for

Answer 18

SUMming them up

Answer 19

that's what the Sigma notation stands for
SUMMATION of all terms from i="start point" to whatever

Answer 20

okay i multiplied all 9 terms, then subtracted 4, and i added THOSE terms up and i got 100. and that is not an answer choice.

Answer 21

well, it's not 100 for one

notice you're meant to change "i" from 2 to 10 and SUM all terms up