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## #1 2009-10-10 22:02:24

soha
Real Member
Registered: 2006-07-07
Posts: 2,530

### Arithmetic Progression sum

Try solving these:-

1) Find the sum of the
a) first 11 terms of AP 2, 6, 10...
b) first 13 terms of the AP -6, 0,6,...
c) first 51 terms of the AP whose second term is 2 and fourth term is 8.

2) Evaluate S12 for arithmetic sequence...

-9,-5,-1,3,7.......

"Let us realize that: the privilege to work is a gift, the power to work is a blessing, the love of work is success!"
- David O. McKay

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## #2 2009-10-11 09:41:01

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

### Re: Arithmetic Progression sum

Hi soha;

By the formula:

Where
Sn = sum to n terms
n is the number of terms
d = constant difference
s1= first term

a)

Formula:

b)

c)

s2 = 2 and s4 = 8 Add them both up and divide by 2 to get 5. This gives you a constant term of 3 (5-2 = 3 , 8 - 5 = 3)

The sequence is:

-1,2,5,8,11...

Last edited by bobbym (2009-10-11 10:08:21)

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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## #3 2009-10-11 19:48:03

soha
Real Member
Registered: 2006-07-07
Posts: 2,530

### Re: Arithmetic Progression sum

Yippee!!!! Right!!!

"Let us realize that: the privilege to work is a gift, the power to work is a blessing, the love of work is success!"
- David O. McKay

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