A mathematical/numerical sequence is, in short, simply a list of numbers placed in a certain order. Homework problems may ask you "what comes next in this sequence?" or "what is the formula for the n-th number in this sequence?"
To answer these problems, start from the second or third number in the sequence to look for patterns. Common patterns to check are--is the n-th number equal to 'a times n + b', is the n-th number equal to the sum of its previous numbers, etc. Let's try an example with an arithmetic sequence:
2, 4, 6, 8, ___
A problem might ask, what number goes in the blank? If you look carefully, you will notice
2 = 1 x 2
4 = 2 x 2
6 = 3 x 2
8 = 4 x 2
which logically follows that for n = 5, we have 5 x 2 = 10. So 10 is the 5-th number in this sequence.
Hope this helps!
2006-07-12 02:30:24
·
answer #1
·
answered by lildragongirl87 1
·
0⤊
0⤋
A sequence means that to every number 1, 2, 3, ... a number is associated. The "input" number is often called index, indicated with the letter i; the numbers in sequence x are written as x_1, x_2, x_3, and in general, x_i.
For instance, the "Fibonacci sequence" is
x_1 = 1
x_2 = 2
x_3 = 3
x_4 = 5
x_5 = 8
x_6 = 13
x_7 = 21
or in short,
x = (1, 2, 3, 5, 8, 13, 21, ...)
Of course, in order to know every number in the sequence (infinitely many!) you need a general rule or formule. In our case, a general rule would be
x_(i+2) = x_(i+1) + x_i
which tells that every number in the sequence is equal to the sum of the two previous ones.
2006-07-22 21:22:13
·
answer #2
·
answered by dutch_prof 4
·
0⤊
0⤋
A sequence is a High School student not doing his/her homework leading to panic leading to desperation leading to silly questions on yahoo! anwers - close?
2006-07-12 09:01:47
·
answer #3
·
answered by jonnygaijin 5
·
0⤊
0⤋