Question

Please help?
Find the sum of the following arithmetic series:
7+12+17+22+...+52
The sum of the series is ___.

Do I just add?
Thank you in advance! :)

Answer 1

hmmmm go on u just need to find the no of terms ...and then u can addd :)

Answer 2

What's the difference between each consecutive number in the sum?

Answer 3

5

Answer 4

Right. And what number does the sum stop at?

Answer 5

so a_1 = 7 and d = 5
and a_n = 52 ....

Answer 6

and also
\[a_n = a_1 + (n - 1)d\]
plug the values u got and get n i.e the no of terms...and find the sum of the series

Answer 7

Yes, I understand that @rishavraj and what do you mean @DurableToaster , the sum of all the numbers?

Answer 8

so now u can proceeed ??@Ray1998

Answer 9

7=52 +(5-1)5 is this correct?

Answer 10

@Ray1998 ???

Answer 11

Are the numbers I plugged in to the formula correct?

Answer 12

nope ...see a_1 = 7 , d = 5, a_n = 52
so
52 = 7 + (n - 1)5

Answer 13

Okay, gotcha.

n = 1 + 5 square root 45
n = 3.14112736

Answer 14

Sorry, my answer wouldn't send in :/

Answer 15

nope thts wrong .... -_-
52 = 7 + 5n - 5
52 = 2 + 5n
50 = 5n
n = 10

so now apply the summation formula

Answer 16

Sorry, I'm really bad with math.
52 = 7 + (10 - 1)5

Answer 17

noope.....u need to use now
\[S_n = \frac{ n }{ 2 }(a_1 + a_n)\]

Answer 18

u got all the values now ......solve it @Ray1998

Answer 19

s = 295/n?

Answer 20

hmmmm why is tht ...??? :/
\[S_{10} = \frac{ 10 }{ 2 }(7 + 52) \]
\[S_{10} = 295 \]

Answer 21

http://prntscr.com/ajp81h tht part makes no sense