# could any1 help me?? ^_^

A) prove that the sum of the first n terms in an arithmetic series is              s = n/2 [2a+(n-1)d] where a =  first term and d = common difference

B) use this to find the sum of the first 100 natural numbers

thanx people ^_^

Posted Thu 8th November, 2012 @ 19:03 by Waqar Khanny :)
Edited by Waqar Khanny :) on Thu 8th November, 2012 @ 19:04

:( ur mean zainab

Answered Sat 10th November, 2012 @ 18:15 by Waqar Khanny :)

Aww! Im not :) LOL

I Jus dont knw the answer :) Hhahhaa

Im sorry :(

I Know ull forgive me because ur amazing <3 **

Edited by adfv on Sat 10th November, 2012 @ 21:21

lol XDD am i??? ;P itz kay i forgive u XDDD

Answered Sun 11th November, 2012 @ 16:38 by Waqar Khanny :)

Yeppp :D Thankyou :D

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Answered Sun 11th November, 2012 @ 16:43 by Waqar Khanny :)

:D Makin me happy :))LOL

and mental at the same time:P

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Answered Sun 11th November, 2012 @ 20:29 by Waqar Khanny :)

Ohh really? hhaha :P i dint knw that!!

LOL XDDD haha welll u knw now ;P

Answered Sun 11th November, 2012 @ 20:34 by Waqar Khanny :)

yehh now i know very well :D ;)

LOL ^_~

Answered Sun 11th November, 2012 @ 21:03 by Waqar Khanny :)

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And the burns still there!! :) see i dnt knw wether i shud be happy or sad, but ima go wiv happy cuz then i remembr u wen i see it :P

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Answered Mon 19th November, 2012 @ 19:01 by Waqar Khanny :)

:D :D

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Answered Mon 19th November, 2012 @ 19:11 by Waqar Khanny :)

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Answered Mon 19th November, 2012 @ 19:15 by Waqar Khanny :)

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Answered Mon 19th November, 2012 @ 19:36 by Waqar Khanny :)

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hhaha yeah dey r XDD hmmm need 2 cum ova soon dont i XDD id lyk 2 put those kisses somewhere XDDD

Answered Mon 19th November, 2012 @ 19:49 by Waqar Khanny :)

Hhahaha! somewheeeere! ooooooooooooooohhh LOL

hmmm yeah some where babe...lool XDDD

Answered Mon 19th November, 2012 @ 19:56 by Waqar Khanny :)

ahahha! an where is that some where? LOOOOL

Edited by adfv on Mon 19th November, 2012 @ 21:55

looool XDD haha ull find out dw.... jus keep waitin innih XDDD

Answered Mon 19th November, 2012 @ 20:24 by Waqar Khanny :)

Hahahhaha! keep waitin! hmm okayy :P (have i ever told you) I LOVE YOU lol!

the sum of the numbers = the number of terms (n) divided by 2 ( 2xthe first number + (n-1)x the difference between each number)

we know the difference = secound term (2) subtracted by the first term (1)

so the difference =1

the formula now looks like this

Sn= 100/2 (2x1+99x1)

So Sn= 50x101

So finnaly the sum of the first 100 natural numbers= 5050

If its unclear how i got that just reply and ill try to explain it better :p

Hope this helps

RTF

Answered Tue 20th November, 2012 @ 09:35 by Ragnaros the Firelord

ermmm yahh kinda iz..soz ragnoras the firelord ((haha)) i got lost :((

Answered Tue 20th November, 2012 @ 16:19 by Waqar Khanny :)

lool zainab keep waitin...haha nd yeah u may have mentioned it XDDD rememba ily 2 :P

Answered Tue 20th November, 2012 @ 16:19 by Waqar Khanny :)

awwwwwwwwwwwwwwwwwwwwww :D