# Math patterns you good?

1. Feb 8, 2006

### runicle

I have no clue what pattern in these sequences have (help):
(i)5,4,9,13,22
(ii)1,2,2,4,8
(iii)1,8,27,64
and can someone give me some advice how to notice patterns.

2. Feb 8, 2006

### z-component

For (i), the first two numbers in the sequence (5 and 4) add up to equal the third number in the sequence (9).

So 5+4=9 and 9+13=22.

3. Feb 8, 2006

4. Feb 9, 2006

### honestrosewater

(ii) Well, 1 * 2 = 2, 2 * 2 = 4, 2 * 4 = 8...
(iii) Not perfect squares, but perhaps perfect something...
I think practice helps (though I suppose how much it helps might depend on how well you can already notice patterns). Here are a few things that come to mind: Look for similarities among the terms, e.g., are they all even, all odd, all multiples of some number, all prime (any primes should usually be a pretty big clue), and so on. Look for a pattern in the differences between successive terms. Note how the terms change, i.e., whether they keep increasing, decreasing, switching back and forth, etc. Break the sequence up into two or more sequences, e.g., by putting every other term in a new sequence.

Last edited: Feb 9, 2006
5. Feb 9, 2006

### Moonbear

Staff Emeritus
Whoah, folks! Runicle, you need to show your own work and effort to get help; please review the forum guidelines regarding homework help questions.

And as a reminder to the "helpers," we give help, not complete solutions! Runicle needs to learn to do this for him/herself.
(HRW, this is not directed at you, but to those whose complete solutions I've just deleted.)

6. Feb 9, 2006

### runicle

I understand Moonbear It's kind of hard to get get help from this question though. Well anyways i found the answer it was:
(ii)1,2,2,4,8
1 x 2 is 2 2 x 2 is 4 2 x 4 is eight. Recursive expression
(iii)1,8,27,64
n^3

7. Feb 9, 2006

### z-component

Yes, but please remember that this post was not made in the Science Education area when I replied. Although he said (help), it as easily have been a general question. Your comment has been noted though. :)