current questions can be found in the first post
Heian-794
Posts: 364/896 |
I just noticed that #11 hasn't been answered. The largest known twin primes are:
665551035 x 280025 +/- 1 |
ziratha
Posts: 18/231 |
#7, is not a prime number im guessing. just a thought. probably wrong. |
neotransotaku
Posts: 1026/4016 |
yeah, that is the right answer 
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Current Point Totals
Heian-794 - 8 points
NSNick - 1 point
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current questions can be found in the first post |
Heian-794
Posts: 264/896 |
The answer to #13 just jumped into my head! Sophie Germain and her prime numbers are of course what you're looking for! |
neotransotaku
Posts: 1016/4016 |
well, i dunno...i was looking for a stronger reason but I guess i can't expect that much out of people...
anyways, yeah, Heian-794, you are right.
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Current point totals
Heian-794 - 7 points
NSNick - 1 point
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current questions can be found in the first post |
Heian-794
Posts: 257/896 |
I think Nick's answer to #6 is perfectly fine -- BTW, when I took the SAT there was a question about whether or not 1 was prime, and, thinking that it was, I got it wrong!
Not so sure how much this has to do with sets, but I'm going to have to say "infinity", (or "aleph" if you're a Cantor fan) for #9.
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neotransotaku
Posts: 995/4016 |
NSNick: alright--i guess i'll have to accept it since i wasn't specific enough  (well, this is the first time i've moderated such a thread so i apologize for my inexperience)
Why I rejected it in the first place because that is a weak reason why I believe -- plus, that isn't the one I had in mind.
So, #6 is still up for grabs, but this time reworded to be: "Give a strong reason why 1 can't be a prime number."
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Current point totals
Heian-794 - 6 points
NSNick - 1 point |
NSNick
Posts: 643/3875 |
What's wrong with my answer?
I just looked it up real quick:
prime number
A number that has exactly two factors, 1 and the number itself (cf Venn Diagrams Discussion).
and...
A prime number is a positive integer that has exactly two positive integer factors |
kornfan
Posts: 301/622 |
6: the definition of a prime number is that its factors include numbers besides itself, and 1. Itself being 1, it can't be prime. |
neotransotaku
Posts: 993/4016 |
6) Nope
7) True but I was looking for something a little less obvious
8) It is Skewes Number, you'll get credit for that--but it doesn't require arrow notation
9) N doesn't represent the Null Set
10) Nope
12) Correct
13) No. The numbers that are named after this woman has a prime quality to them.
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Current Point Totals:
Heian-794 - 6
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The list of questions (answered or unanswered) can be found in the first post of this thread. |
Heian-794
Posts: 252/896 |
7. It has almost four thousand consecutive zeroes in it!
8. The Skewes number, useful in Ramsey theory, is ludicrously huge and needs special "arrow notation" to be expressed. (Arrow notation: I'll write an A since western encoding doesn't contain an arrow. In short, 3 A 3 means 3 ^ 3 ^ 3, or a tower of successively exponentiating threes. Imagine what 99999 A 99999 would look like.)
10. This equals 1 + (1 + 2/11), which is... uhh... almost exactly 0.7 less than e?
12. A repunit is a number like 111, 11111111, etc. Many of these have interesting properties which I can't be faffed to look up right now.  ;
13. Does this have anything to do with Catalan numbers by any chance?
No time to research anything today; this stuff is by the seat of my pants!
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NSNick
Posts: 635/3875 |
6) I believe the definition of prime numbers is that they have exactly two factors. 1 only has one factor- itself.
9) The null set?
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neotransotaku
Posts: 989/4016 |
okay...my bad...real life got into my way
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anyways...
Heian will get #5 since the chinese were the first to use it. I had the people from India in mind but they were the first to allow negative numbers in their mathematic system. Basically, my question was worded incorrectly XD
Cross multiplication answer for #1 is incorrect. that is not the "official" name of the method.
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Point totals
Heian-794 - 4 points
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Questions:
1) We all learned to multiply by hand in elementary school and there were steps to multiply numbers more than 1 digit. For example, to multiply 11 x 12, we would write down something that will look like this in the end.
11
x12
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22
11
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132 Therefore, the question is this: What is the name of this method?
6) Why can't 1 be a prime number?
7) What is special about this prime number: (101951) x (101975 + 1991991991991991991991991) + 1
8) What is the largest number that is considered useful in mathematics?
9) What does N represent in N + 1 = N? (Hint: it deals with sets)
10) What is special about this: 1 + (1 / (5 + (1/2)))
11) How many digits are the largest known twin primes?
12) What's a repunit?
13) What woman has a type of number named after her? |
Cymoro
Posts: 850/2216 |
Originally posted by neotransotaku
1) We all learned to multiply by hand in elementary school and there were steps to multiply numbers more than 1 digit. For example, to multiply 11 x 12, we would write down something that will look like this in the end.
11
x12
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22
11
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132 Therefore, the question is this: What is the name of this method?
Cross multiplication.
5) Which civilization was the first documented civilization to use negative numbers?
If my history class was right, China. |
kornfan
Posts: 224/622 |
Perhaps we should guess continuously until we get it right. Sparta. I'm out of ancient civilations. Oh yeah. maya inca aztec |
Heian-794
Posts: 241/896 |
Are we going to get an answer to this one, Neo, or what? |
kornfan
Posts: 206/622 |
I'm going to guess that 5 is either greece, or phoenecia. |
Apocalypse
Posts: 198/203 |
Is Question 5 the egyptians? |
Heian-794
Posts: 177/896 |
It's not the Japanese. They have however gotten really good at using negative numbers in recent years, what with them popping up on investment return-relsted charts all the time!
I'll say the Indians were the first to do mathematics with negative numbers. IIRC, they used colors for different variables rather than the letters that we use. |
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