Question

http://prntscr.com/ayudw2

Answer 1

@johnweldon1993 wait lemme try it first

Answer 2

b?

Answer 3

That's wrong

Answer 4

Incorrect.

Answer 5

Are you guessing or did you work it out?

Answer 6

i plugged in 12 for n. but i guess its not that easy

Answer 7

okay wait

Answer 8

what do you know about summations?

Answer 9

Sigma is when you take 1,2,3,4...12 and plug them all into the equation and add them all together.

Answer 10

ohhhh okay that makes sense okay lemme do it

Answer 11

You should see a pattern which would make this really easy, for each value you input, the outcome is only two higher.

Answer 12

this is an arithmetic problem right?

Answer 13

Yes, I believe so, since you are only adding two for each new input.

Answer 14

@rebeccaxhawaii yup its its arithmetic sum

Answer 15

its Z

Answer 16

\[S _{n} = n*(a _{1}+a _{n}) /2\] @rebeccaxhawaii use this rule