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what is the next number(s) in the sequence?

bonus points if you can also add the formula for each seaquence

1) 1.5, 5, 11.5, 20, 27.5 ...

2) 2.25, 1.5, 1.41666666(recurring), 1.5, 1.65 ...

3) 1, 0, -3, -8, -15 ...

4)3.2, 1.9, 1.6, 1.55, 1.6 ...

p.s. can you use spoiler boxes

good luck

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thats right can someone give me a formula

or any of the other sequences

I actually didn't create a formula, i just noticed a pattern.

-1, -3, -5, -7.. go up by odd numbers and subtract them.

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I actually didn't create a formula, i just noticed a pattern.

-1, -3, -5, -7.. go up by odd numbers and subtract them.

Weeeeellllllllll..........I think a formula could be described as a pattern, as long as the changes are always the same rate, or something like that...:)

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what is the next number(s) in the sequence?

bonus points if you can also add the formula for each seaquence

1) 1.5, 5, 11.5, 20, 27.5 ...

2) 2.25, 1.5, 1.41666666(recurring), 1.5, 1.65 ...

3) 1, 0, -3, -8, -15 ...

4)3.2, 1.9, 1.6, 1.55, 1.6 ...

p.s. can you use spoiler boxes

good luck

All starting at x = 0:

  1. (x^4 / 12) + (x^3 / 3) + (13 * x^2 / 12) + (13 * x / 6) + 1.5
  2. (x^4 / 60) - (11 * x^3 / 60) + (23 * x^2 / 30) - (27 * x / 20) + (9 / 4)
  3. 1 - x^2
  4. (x^4 / 40) - (11 * x^3 / 40) + (23 * x^2 / 20) - (11 * x / 5) + (16 / 5)
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everyone is over-complicating it here is the formulas i got

1) 1.5, 5, 11.5, 20, 27.5 ... (n/2)+(n^2)

2) 2.25, 1.5, 1.41666666(recurring), 1.5, 1.65 ...n/4 + 2/n

3) 1, 0, -3, -8, -15 ... 2n-n^2

4)3.2, 1.9, 1.6, 1.55, 1.6 ... (3/n)+(n/5)

Edited by theshredder157
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just guess, no formula

1. next is 80...it's N2x4,for each even number of it...for odd can't figure out the formula yet

2. maybe 1.5- every second member is 1.5.....

3. it's always minus odd number so next is -24, -35....

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All starting at x = 0:
  1. (x^4 / 12) + (x^3 / 3) + (13 * x^2 / 12) + (13 * x / 6) + 1.5
  2. (x^4 / 60) - (11 * x^3 / 60) + (23 * x^2 / 30) - (27 * x / 20) + (9 / 4)
  3. 1 - x^2
  4. (x^4 / 40) - (11 * x^3 / 40) + (23 * x^2 / 20) - (11 * x / 5) + (16 / 5)

yeah......Of course you can increase the degree of the polynomial and throw it all in a matrix to get coefficients that will work....but do you really think the author meant for all these to be high degree polynomials?

And theshredder157...you missed #1 (your 2 is equivalent to mine). But great job getting number 4 (I'm not positive that's correct since I didn't write the problem....but it's nice and concise)

I just noticed that you (theshredder157)are the op. You apparently have some errors in the lists you provided if those are the right formulas.

Edited by EventHorizon
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i made up the sequences and formulas from scratch and i double checked it all on a calculator

i cant see a mistake in my math

maybe we read the formulas differently or something

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