Shoutbox

Programing languages (and the Svip, more importantly ) agree.
Our hypothesis of zeroness must be correct!

I solved them too by taking the formulas I know and then adjusting them to the ones similair by your sequences:

code:

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1,3,6,10
y = (number/2) * (first + last)
y = (x/2)(x+1) = (x*x +x)/2

3, 6, 10, 15, 21
y = (x+1)(x+2)/2 = (x*x + 3x + 2)/2


1,2,4,8
y = g ** x
y = 2 ** (x - 1)

8, 16, 32, 64, 128
y = 2 ** (x + 2)

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Edit: I assumed y(1) is the first value in both sequences.
Edit2: Power/multiplication typo. I prefer ** for powers.

quote:

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Originally posted by somelauw
I solved them too by taking the formulas I know and then adjusting them to the ones similair by your sequences:

code:

---

1,3,6,10
y = (number/2) * (first + last)
y = (x/2)(x+1) = (x*x +x)/2

3, 6, 10, 15, 21
y = (x+1)(x+2)/2 = (x*x + 3x + 2)/2


1,2,4,8
y = g * x
y = 2 * (x - 1)

8, 16, 32, 64, 128
y = 2 * (x + 2)

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Firstly, refer to my post earlier in this thread.
Secondly, expression 1 is wrong. I mean the pattern you've considered isn't the one he wants...
The first expression is correct since its a standard. Its usually written as x*(x+1)/2
In the second expression, you are missing the condition where the first value (initial value) is to be taken as x=0; Your expression would be correct if you would have considered that. (read my post for a complete explanation)
Third expression is horribly wrong. You've mixed up multiplication and exponentiation
Fourth expression is wrong because the series is the power of 2 series. You're multiplying 2 with numbers like 3,4,5,6 which won't give you the answers. What you needed was the raised to (also called exponential; noted as ^) and not the multiplication sign. If you replace the multiplication by exponentiation and consider the zero criteria (as mentioned in my post, your answer would be correct)

JA, you're right. I corrected my mistakes.
I didn't remember whether 0 or 1 should be taken as first number for x. I though that both where acceptable.
For powering I prefer the ** sign, because ^ could also stand for bitwise xor. I only made a slight typo by forgetting to double the *.

quote:

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Originally posted by somelauw
For powering I prefer the ** sign, because ^ could also stand for bitwise xor. I only made a slight typo by forgetting to double the *.

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yeah, ^ is bitwise ex-or but that's in programming, something we're not referring to now. ** would have worked too

quote:

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Originally posted by Phillip

quote:

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Originally posted by Bilbo
There are two patterns that I couldn't figure out, and nither could my teacher when I asked her.

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Wow your math teacher must be kinda stupid =\

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Well it is Canada.


.. J/k!!

quote:

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Originally posted by John Anderton
They start with n=0, fool (Smilie)
He said, initial value is 3. Implies for n=0, value=3; Then next value is 6 implies for n=1, value=6.

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quote:

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Originally posted by Bilbo
Pattern: 8, 13, 18, 23, 18, 33
Description: Start at 8 then add 5.
Expression: n5+3

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1*5+3 =8

and my name is foaly not fool

quote:

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Originally posted by John Anderton
Programing languages (and the Svip, more importantly ) agree.
Our hypothesis of zeroness must be correct!

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Well except if you deal with maths programs like matlab, then it starts from 1, but that is becausethey store every variable in a matrix (2 dimensional array)