Question

Find the sum of the arithmetic series.

Answer 1

11 + 15 + 19 +... + 83

Answer 2

common difference d= ... ?

Answer 3

yes, now you only need number of terms n to be able to use the formula

Answer 4

83?

Answer 5

no, thats tn = last term
we need n

Answer 6

use this formula
tn = t1+ (n-1)d
where t1 = first term =11
tn = 83
d=4

Answer 7

you'll get, n :)

Answer 8

oh 339?

Answer 9

noo...

Answer 10

83 = 11 + (n-1)*4

Answer 11

ohh ok I see what you did, it's a little different from the last one you helped me with...

Answer 12

yep, in last one, n was known, here we need to find it

Answer 13

ok so n= 19

Answer 14

yes!

Answer 15

and overall sum =... ?

Answer 16

893

Answer 17

\(\huge \color{red}{\checkmark \quad \ddot \smile}\)

Answer 18

how did you write that cool smiley face? haha

Answer 19

using latex!
to make that smiley and checkmark, i used this code

`\(\huge \color{red}{\checkmark \quad \ddot \smile}\)`

Answer 20

wow that's cool! I may post another question because now I'm working with geometric series.. hopefully you'll be on... thanks for the help!

Answer 21

sure :)

Answer 22

\(\huge \color{red}{\quad \ddot \smile}\)

Answer 23

you learn quickly! :D