Problem 002

harryh · Post by **harryh** » Sat Oct 16, 2010 8:10 am

@phillyj : Please don't start a new thread (topic) if one already exists for the same problem.

antonwahyu · Post by **antonwahyu** » Sun Oct 24, 2010 12:00 pm

hi guys,
sorry i still not understand about this sentence, maybe can translate to me to Indonesian?
in this case, "Find the sum of all the even-valued terms in the sequence which do not exceed four million"
i am not understand about this sentence.. somebody can translate for me...i put my answer and the result is wrong, maybe i not yet understand about the question. so what the mean about the question. for example if 4 million change to 10. what the result? is it to be 1,2,3,5,8 right? and the answer is 8? or 1+2+3+4+5+8 = 23? any body help me? thanks before

hk · Post by hk » Sun Oct 24, 2010 12:05 pm

if you change 4 million to 10 the answer would be 2+8=10.
Why? 2 and 8 are the fibonnacci numbers less than 10 that are even. (an even number is a number that is divisible by 2).

cobrophy · Post by **cobrophy** » Thu Dec 23, 2010 3:54 pm

Hi,

I spent a while getting this wrong because I misunderstood the problem statement:

Find the sum of all the even-valued terms in the Fibonacci sequence which do not exceed four million.

I incorrectly thought the not exceeding 4 million referred to the sum rather than the even-valued terms.

It might be a little clearer if the problem was phrased as:
Find the sum of all the even-valued terms under four million in the Fibonacci sequence.

euler · Post by **euler** » Fri Dec 24, 2010 9:00 am

This has been addressed before. Contrast the following two sentences.

Find the sum of all the even-valued terms in the Fibonacci sequence which do not exceed four million.
Find the sum of all the even-valued terms in the Fibonacci sequence which does not exceed four million.

The antecedent to "which" is identified by the use of the verb: "which do" refers to the terms (plural); "which does" refers to the sum (singular).

However, given the regularity to which this is creating confusion - and it's not like we're trying to test subtle use of grammar - so I'll change it to the following...

By considering the terms in the Fibonacci sequence whose values do not exceed four million, find the sum of the even-valued terms.

sunde887 · Post by **sunde887** » Wed Jan 05, 2011 3:12 am

edit: figured it out.

rayfil · Post by **rayfil** » Wed Jan 05, 2011 5:40 pm

(I hope this isn't a spoiler, I apologize if it is)

Regardless if posted results are correct or not, the opening message is clear, i.e. don't post any code or results.

wygk123 · Post by **wygk123** » Wed Feb 09, 2011 2:46 pm

The Java solution:

code snipped by hk
}

hk · Post by hk » Wed Feb 09, 2011 3:06 pm

This forum is not meant to post solutions. Please remove it.

arnaud.nauwynck · Post by **arnaud.nauwynck** » Thu May 19, 2011 9:56 pm

Hi,

I am new to this site, and I have just done problem 002.
I have done it 2 ways...
1) the hard way (pure math + simple calculator), and I have found an algebraic formula for the answer
2) and then using a small algorithm with few lines of code... mainly for checking.

After I have submitted my result, I have read many comments on the solution (the official pdf, then posts among the 250 ones), but I was disapointed by the official solution shown, and the solution forum is closed ...
Is there an administrator to re-open it, or someone wanting my closed-formula solution by email ?
I understand that its written not to deliver the solution in public forums, so I don't write it here...

Sincerely,

hk · Post by hk » Thu May 19, 2011 10:04 pm

You can PM your solution to me as I wrote the pdf.

arnaud.nauwynck · Post by **arnaud.nauwynck** » Thu May 19, 2011 11:33 pm

did you received the email ?

hk · Post by hk » Fri May 20, 2011 9:01 am

I did. I will investigate it and send you a reply.

rjgonza · Post by **rjgonza** » Tue Jun 14, 2011 12:11 am

I am having a little trouble with this one. I think I may be interpreting the question incorrectly. The value in question is the actual terms of the sequence, not the corresponding position in the sequence correct? If that is the case then I am not sure why my code is not working. Would I be able to pm it to someone to give it a quick glance?

TripleM · Post by **TripleM** » Tue Jun 14, 2011 2:31 am

Sure.

243009558he · Post by **243009558he** » Tue Jul 19, 2011 2:19 pm

Code snipped by hk.

stoop65 · Post by **stoop65** » Sat Jul 30, 2011 1:07 pm

Hi Euler Team,
Regarding problem two, the Fibonacci sequence starts like this:

F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 F10
0 1 1 2 3 5 8 13 21 34 55..., *

but the problem outline starts with the terms 1 and 2 (F2 and F3). This would change the solution.
Where should I start? Semantics, I know, but problem 1 caught me out with semantics ("...3 OR 5...").

Thanks in advance for a clarification,

Steve.

* (Thank you Wikipedia: http://en.wikipedia.org/wiki/Fibonacci_ ... ci_numbers )

hk · Post by hk » Sat Jul 30, 2011 1:33 pm

The answer is NOT affected as you are asked for the sum of the even-valued terms.

Duffmancool · Post by **Duffmancool** » Tue Jul 16, 2013 6:59 am

There is an error on the problem description.

The Fibonacci sequence does not go: 1,2,3,5,...
It goes: 0,1,1,2,3,5,...
Or maybe even: 1,1,2,3,5,...

http://en.wikipedia.org/wiki/Fibonacci_number
http://en.wikipedia.org/wiki/File:FibonacciBlocks.svg

hk · Post by hk » Tue Jul 16, 2013 9:17 am

Or even:
1,0,1,1,2,3
Or
-1,1,0,1,1,2,3
Or
2,-1,0,1,1,2,3

So I'm not sure what you try to tell us.

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