Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °

You are not logged in.

## #1 2009-10-11 21:02:24

soha
Real Member

Offline

### 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

## #2 2009-10-12 08:41:01

bobbym

Offline

### 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...

Glad to help ya!!!

Last edited by bobbym (2009-10-12 09:08:21)

In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

## #3 2009-10-12 18:48:03

soha
Real Member

Offline

### 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