Monday, April 22, 2013

9.1 Intro to Sequences

I know this is a week late, but better late than never!

This section is on the basics of sequences. But what is a sequence?

Sequence: function whose domain is an ordered set of natural numbers

There are two ways to define sequences.

Explicit form:
Will tell you any term



The first five terms of the sequence are...
n
1
2
3
4
5
an
1
3
5
7
9




Recursive form: 
All terms are defined using previous terms




a1 = 1
ak+1 = ak + 2


The first five terms of the sequence are...
k
1
2
3
4
5
ak
1
3
5
7
9

It's the same sequence as before, but it's written differently. 




Some common sequences we may see are....

n2: 1, 4, 9, 16, 25…
n3: 1, 8, 27, 64, 125…
2n: 2, 4, 8, 16, 32…
3n: 3, 9, 27, 81…
n! (factorial): 1, 2, 6, 24, 120…
Fibonacci: 1, 1, 2, 3, 5, 8, 13, 21…

So, it wasn't very long but that's the introduction to sequences!

Carly


No comments:

Post a Comment