Math Is Fun Forum

anyarules

Member

Registered: 2005-07-24

Posts: 29

number sequences

pls complete this::

* 81  27  135  45  __  75  __

* 4  10  18  28  40  __  __  __

* 11  20  27  __  35  36

thanx guys!!;):D:cool:

Ricky

Moderator

Registered: 2005-12-04

Posts: 3,791

Re: number sequences

1.  /3, *5, /3, *5...
2. +6, +8, +10, +12, ....
3. +9, +7, +5, +3, +1

Last edited by Ricky (2006-02-18 12:38:35)

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"In the real world, this would be a problem.  But in mathematics, we can just define a place where this problem doesn't exist.  So we'll go ahead and do that now..."

anyarules

Member

Registered: 2005-07-24

Posts: 29

Re: number sequences

thanx
but i'm cause no answers?

but man!

Last edited by anyarules (2006-02-19 18:26:43)

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 48,423

Re: number sequences

anyarules, Ricky gave the clues. I shall give the answers.

* 81, 27, 135, 45, 225 , 75, 375

* 4, 10, 18, 28, 40, 54, 70, 88

* 11, 20, 27, 32, 35 , 36

   

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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.

Ricky

Moderator

Registered: 2005-12-04

Posts: 3,791

Re: number sequences

anyarules, Ricky gave the clues. I shall give the answers.

I just did that because I know that ganesh is clueless.

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"In the real world, this would be a problem.  But in mathematics, we can just define a place where this problem doesn't exist.  So we'll go ahead and do that now..."

sabdulsamee

Member

Registered: 2006-05-11

Posts: 9

Re: number sequences

I have a sequence to share with everyone
Its name is Even Squares and it goes like this: 4, 16, 36, 64, 100, 144, 196, 256, 324, 400, 484, 576, 676, 784, 900, 1024, 1156, 1296, 1444, 1600, 1764, 1936, 2116, 2304, 2500, 2704, 2916, 3136, 3364, 3600, 3844, 4096, 4356, 4624, 4900, 5184, 5476, 5776, 6084, 6400, 6724, 7056, 7396, 7744, 8100, 8464, 8836, 9216, 9604, ...

sabdulsamee

Member

Registered: 2006-05-11

Posts: 9

Re: number sequences

I have a sequence to share with everyone
Its name is Even Squares and it goes like this: 4, 16, 36, 64, 100, 144, 196, 256, 324, 400, 484, 576, 676, 784, 900, 1024, 1156, 1296, 1444, 1600, 1764, 1936, 2116, 2304, 2500, 2704, 2916, 3136, 3364, 3600, 3844, 4096, 4356, 4624, 4900, 5184, 5476, 5776, 6084, 6400, 6724, 7056, 7396, 7744, 8100, 8464, 8836, 9216, 9604, ...

These are the first 49 terms of the sequence of which
the first term is 4,
the second term is 16, and
the third term is 36. Now
     4 is   2 times  2, and   2 is  1 plus  1.
   16 is   4 times  4, and   4 is  2 plus  2.
   36 is   6 times  6, and   6 is  3 plus  3.
   64 is   8 times  8, and   8 is  4 plus  4.
100 is 10 times 10, and 10 is  5 plus  5.
144 is 12 times 12, and 12 is  6 plus  6.
196 is 14 times 14, and 14 is  7 plus  7.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 48,423

Re: number sequences

Hi sabdulsamee,
Welcome to the forum.
The nth term of the series you have given is (2n)²,
thus the first term would be (2 x 1)²=2² = 4
and the second would be (2 x 2)²=4² = 16, and so on.
The differences of the terms of this series would form an Arithmetic Progression.
The differences are 12, 20, 28, 36, 44, 52, .....
You can see that the common difference of the terms in the series is 8.

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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.