Math Is Fun Forum

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

You are not logged in.

#1 2006-03-13 11:14:12

4littlepiggiesmom
Member
Registered: 2006-01-09
Posts: 42

Find sum of 100 terms in a sequence?

My daughter had to miss math class for a music event and wants me to check her answers??? So here I am looking for help~

Find the sum of the first 100 terms of the aruthmetic sequence 19, 13 ,7,.....?  We came up with b

a. -58,100
b. -556
c. _27,800
d. -55,600
e. nnone of these

Offline

#2 2006-03-13 15:03:06

George,Y
Member
Registered: 2006-03-12
Posts: 1,379

Re: Find sum of 100 terms in a sequence?

c, and there is a little trick-- notice c is one half of d, and think what's in the examiner's mind to do so


X'(y-Xβ)=0

Offline

#3 2006-03-14 00:11:36

4littlepiggiesmom
Member
Registered: 2006-01-09
Posts: 42

Re: Find sum of 100 terms in a sequence?

Thanks!

Offline

#4 2006-03-19 01:01:29

Jenilia
Member
Registered: 2005-07-09
Posts: 64

Re: Find sum of 100 terms in a sequence?

What is a aruthmetic sequence?


Ideas are funny little things, they won't work unless you do.

Offline

#5 2006-03-19 01:13:18

Jai Ganesh
Administrator
Registered: 2005-06-28
Posts: 45,956

Re: Find sum of 100 terms in a sequence?

An Arithmetic Progression or sequence is such that the difference between any two successive terms of the series is the same. For example,
(1) 2, 5, 8, 11, 14, 17, ...
(2) 1, 5, 9, 14, 17, 21, .....
(3) 15, 13, 11, 9, 7, 5, 3, 1, ...
(4) 0.5, 2, 3.5, 5, 6.5, 8, 9.5 etc.
You can see that the difference between any two consecutive terms is always the same for the entire series. In example (1), it is 3, in (2) it is 4, in (3), it is -2 and in (4) it is 1.5.
The first erms of the Aritmetic Series or Progression is denoted by 'a' and the common difference by 'd'.
The nth term, tn is given by tn= a+(n-1)d and
the sum of n terms is given by
Sn= n/2[2a+(n-1)d] smile


It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Offline

Board footer

Powered by FluxBB