Problem 080
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Don't start a new topic for a problem if there already exists one
See also the topics:
Don't post any spoilers
Comments, questions and clarifications about PE problems.
Re: Problem 080
3, 99 are correct.
5, 50 are wrong  5 is actually relatively far off.
5, 50 are wrong  5 is actually relatively far off.
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 PurpleBlu3s
 Posts: 75
 Joined: Mon Sep 19, 2011 6:49 pm
Re: Problem 080
I think I found the problem, is 474 correct for sqrt 5?jaap wrote:3, 99 are correct.
5, 50 are wrong  5 is actually relatively far off.
 PurpleBlu3s
 Posts: 75
 Joined: Mon Sep 19, 2011 6:49 pm
Re: Problem 080
Nevermind, it must have been because I got the answer.
Re: Problem 080
It's better, but still false.PurpleBlu3s wrote:I think I found the problem, is 474 correct for sqrt 5?
Entia non sunt multiplicanda praeter necessitatem
 PurpleBlu3s
 Posts: 75
 Joined: Mon Sep 19, 2011 6:49 pm
Re: Problem 080
Yes, 473. :>Francky wrote:It's better, but still false.PurpleBlu3s wrote:I think I found the problem, is 474 correct for sqrt 5?
It was an issue with rounding.
Problem 080
So I have written an algorithm for problem 80, and I ended up with the wrong answer of 40909. What I don't get about this is that I have the correct sum for the square root of 2, and I also have the correct number for the square root of 99. Am I missing something? I sum without the perfect squares, and I include the first number for the digital sum. I can't see where my algorithm is going wrong, and yet the sum keeps getting rejected. Any suggestions?
Re: Problem 80
Here's the forum thread for problem 80: viewtopic.php?f=50&t=1198
I suspect you're making a mistake that has been mentioned in some posts there.
I suspect you're making a mistake that has been mentioned in some posts there.
Re: Problem 80
I don't think I am. I know that my method, which is a binary go by digit, won't do rounding, and I went out super far to double check that. I am including the first digit, so that's not the problem either. I can't get why I would be getting the right number for sqrt(99), but not the right total sum.
Just to check, the digit sum for 99 is 446, right?
Just to check, the digit sum for 99 is 446, right?
 PurpleBlu3s
 Posts: 75
 Joined: Mon Sep 19, 2011 6:49 pm
Re: Problem 80
Yes, but you have to have every square root digital sum correct not just 2 and 99. Check if you are getting it right for other values  it's likely some are wrong.cptroot wrote:I don't think I am. I know that my method, which is a binary go by digit, won't do rounding, and I went out super far to double check that. I am including the first digit, so that's not the problem either. I can't get why I would be getting the right number for sqrt(99), but not the right total sum.
Just to check, the digit sum for 99 is 446, right?
Re: Problem 80
Does anybody have a list of sums they could pm me? I'm interested in finding out the right answer, but I have no idea where my bug is, especially because it seems to be getting so much right.
 PurpleBlu3s
 Posts: 75
 Joined: Mon Sep 19, 2011 6:49 pm
Re: Problem 80
If you pm me your sums I can compare them to mine.cptroot wrote:Does anybody have a list of sums they could pm me? I'm interested in finding out the right answer, but I have no idea where my bug is, especially because it seems to be getting so much right.
Problem 080
Should I be accounting for any leading zeros that will fall off when the rightmost digits are isolated? For instance if the square root of N is 5.02, is the first digit 0 or 2?
Re: Problem 80
There is already a thread for problem 080 here.
In it you will find the answer to your question, which is that the first digit in your example is actually 5.
In it you will find the answer to your question, which is that the first digit in your example is actually 5.
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Re: Problem 080
Topics merged.

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Re: Problem 080
I think it's ridiculously stubborn on the part of the mods to refuse to alter the wording of the question. Many people have been thrown off by the phrase 'decimal digits' which is assumed to imply the digits after the decimal point. If you insist on retaining the current formulation of the question, the least you can do is include a note about this.