Math Is Fun Forum

  Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °

You are not logged in.

#51 Re: Help Me ! » Fibonacci paper » 2009-03-29 09:42:59

Mathysperson: That was my biggest concern. I had a long talk with my Professor about how it read like a sloppy merging of two different papers, and I'm still not happy with the result.

Has anyone taken the chance to look at the Appendix (research paper supplement)? It's less engilshy, but I was hoping someone could look over the math.

Thanks again.

#52 Re: Help Me ! » Fibonacci paper » 2009-03-29 08:40:12

Wow, thanks for the positive feedback, but to be honest I was hoping for something more negative.

Thank you everyone, and it's not due for another week so if anyone has any suggestions, please let me know!

#53 Re: Help Me ! » Fibonacci paper » 2009-03-29 05:03:50

http://www.mediafire.com/?sharekey=f695 … f6e8ebb871

It's pretty diagram heavy, so I guess this is the best way to do it. I'm a little more concerned with the supplement file, I'm not sure if I did the induction the right way (I'm familiar with induction, but I often get hung up on some particulars). It's lengthy, but any feedback would be absolutely wonderful.

Thanks

#54 Help Me ! » Fibonacci paper » 2009-03-28 12:33:32

bossk171
Replies: 9

I've written a paper on beauty in mathematics for my English 101 class that uses the Fibonacci sequence to show why I feel math is an art and not a science. I'm wondering if anyone would be willing to look it over... If so, what's the best way to make a copy available to read? Is there a way to upload an attachment or do I have to give out my email? It's currently saved as a word (2003) file.

Thanks in advance.

#55 Re: Help Me ! » line intersection » 2009-03-23 10:55:11

I asked a similar question a while back. Nothing ever became of the game I was working on, but the response (similar to those here) were very helpful:

http://www.mathisfunforum.com/viewtopic.php?id=8541

It seems as though Luca-Deltodesco is a bit of an expert on the subject...

#56 Re: This is Cool » 0. the number of mystery and emptyness » 2009-03-21 15:44:36

JaneFairfax wrote:

Let me know if you think the poster called Megabrain is an idiot. dizzy

Comments like these are the reason I'm not more active on this forum.

#57 Re: This is Cool » Square Root Photograph » 2009-03-09 07:39:09

I was looking around for stuff on pi day and found this:

http://letsplaymath.wordpress.com/2009/ … -root-day/

A little late, but better late than never...

#58 Re: Help Me ! » Proof of the sum angle identity » 2009-03-02 18:44:16

Ricky wrote:

So what are you looking for?

Something I can show to a Trig student (who hasn't taken calculus). e^ix won't really cut it anyways because you need calc to prove Taylor Series (at least that's the only way I know how to do it) and in order to take the derivative of the trig functions you need to know the sum angle formulas. It's circular reasoning, right?

I like Kurre's picture, thanks! That's definitely something I can use. Does anyone else have anything else to offer?

#59 Help Me ! » Proof of the sum angle identity » 2009-02-28 12:14:51

bossk171
Replies: 3

I'm looking for an easy to understand proof of the sum angle formulas. The best I can find is Wikipedia's (http://en.wikipedia.org/wiki/Proofs_of_trigonometric_identities#Angle_sum_identities)

Also, no fair using Euler's Formula, I know that, but that's not really what I'm looking for.

Any help (links, explanations, proofs, books, etc...) would be very much appreciated.

Thanks!

#60 Dark Discussions at Cafe Infinity » Book Reviews » 2009-02-24 04:52:36

bossk171
Replies: 0

Everyone on at my favorite forum (this one) has some special skill that they contribute. I've thought long and hard about what mine could be, I'm not especially good at math (although I very much enjoy it), I have very little patience, and I'm not particularly level headed. But I do read a lot, and mostly math books at that. So I thought I could start reviewing the books I read, and my reviews might serve some purpose to someone.

This is a trial run. I'm starting with a classic book that (hopefully) many of you read, that way you can send all sorts of feedback my way. I'll keep posting reviews until someone asks me to stop. If there's a book you want me to review, let me know. If you feel that my writing style is no good, let me know. If you have something to add, or grammar correction, of a review of your own, please post it.

Also, a question for the mods, as time goes by and I have another review to add, should I edit this post, or post a new one?

With out further ado (I really am long winded, aren't I)....

-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------


Flatland
By Edwin A. Abbott

Math Quality: 8/10
Readability: 9/10
Overall: Must Read!

     I know it might be a bit cliché to say it, but Flatland really is a really great book. It was written in 1884 but is still relevant in many ways. Equal parts cultural commentary and math book, Flatland is a fictional story about a square (naturally named “A. Square”) and his interactions with a sphere from “spaceland.”

     Being a flatlander, A. Square lives only on a two-dimensional plane, there is no such thing as “up” or “down.” His interactions with the sphere open his mind and the reader’s mind as well. As he starts to understand the third dimension, we may begin to understand the fourth. Dimensional analogies quickly give way to religious metaphors, but the mathematical content is contained. It is completely devoid of any formulas or equations, which makes it a pretty good gateway math book (use it to get your friends hooked on math! What could be better?)

     Being an older book, it does have some clunky qualities, and depending on your reading style, you might consider it to drag in spots, but any shortcomings it has due to age are very much balanced by the classic quality it possesses. It’s also very interesting in a historical context (consider its horrific treatment of women as a satire of Victorian age society). It's quite amazing that as a reader you eventually find yourself caring and rooting for geometric shapes, Who would have thought? Geometry lovers will smile continuously while reading this book, geometry haters might find out geometry is not actually all that bad. A powerful mixture of quaint and profound, Flatland has something to offer for all ages.

     NOTE: I’ve noticed that there’s an “Annotated Flatland” as well as an “Illustrated Flatland” I have not read either.

#61 Re: Euler Avenue » mutilated chessboard variations » 2009-02-19 10:16:00

Cool proof TheDude.

How about if any two (oppositely colored) squares are removed on and 8x8 board (or more generally a 2^n x 2^n board) can it still be covered with dominoes? I haven't put any thought into this yet, I just want to keep up the momentum. I would think that the proof would be a lot the one The Dude wrote for Mathsyperson's variation, but with minor changes...

EDIT: I like Mathsyperson's proof too, it just took me a few more minutes to get it.

#62 Re: Euler Avenue » mutilated chessboard variations » 2009-02-19 04:24:32

Isn't how I color it arbitrary? I purposely removed that spot because it would give me 21 each of A,B, and C.

When yo say antidiagonal, do you mean vertical or horizontal? If so, I would think that wouldn't make sense... I tried to "color" it so that any triomino place would have to cover and A, B, and C (like a domino has to cover a black and a white). If I cover it vertically than it would be possible to lay a triomino that would cover 3 As (or Bs or Cs) which doesn't seem right...

I'm not trying to be difficult, I honestly am having trouble getting this. Am I missing something very simple... I think  am.

#63 Re: Euler Avenue » mutilated chessboard variations » 2009-02-18 13:19:03

mathsyperson wrote:

It's impossible for the straight trionimo. The proof is similar to the standard one, just label the board with three colours instead of two.

I tried that, but I'm pretty sure I missed something:

A B C A B C A B
C A B C A B C A
B C A B C A B C
A B C A B C A B
C A B C A B C A
B C A B C A B C
A B C A B C A B
C A B C A B C

There are 21 each of A,B and C. The original proof relied on there be a different number A squares and B squares.

#64 Euler Avenue » mutilated chessboard variations » 2009-02-18 09:51:40

bossk171
Replies: 10

The mutilated chessboard problem is a very popular classic math puzzle. If you're not familiar with it, google "mutilated chessboard" and read the proof as to why it's impossible, it's pretty cool. Essentially it boils down to the question, "If two opposing corners of a chessboard are removed, can the mutilated board be completely covered with 31 dominoes in such a way that each domino covers 2 squares?"

Let's discuss variations on this problem here!

Variation 1: Consider an 8x8 chessboard with one corner missing (so a total of 64-1=63 squares). Can it be covered with 21 triominoes (dominoes that are 3*1 squares instead of the traditional 2*1)? What if the triominoes are in an L shape instead of a line?

Board with one corner missing:
______________
|_|_|_|_|_|_|_|_|
|_|_|_|_|_|_|_|_|
|_|_|_|_|_|_|_|_|
|_|_|_|_|_|_|_|_|
|_|_|_|_|_|_|_|_|
|_|_|_|_|_|_|_|_|
|_|_|_|_|_|_|_|_|
|_|_|_|_|_|_|_|                                                __
               _____                                              |_|_
triomino: |_|_|_|          trinomino (L variation):  |_|_|

Based on playing around with pictures my suspicions are no, a board with a missing corner piece cannot be covered, but I lack a proof.

So go ahead, post your variations here!

(PS: anyone who wants to produce some legitimate pictures as apposed to my sloppily typed one is more than encouraged to).

#65 Re: Dark Discussions at Cafe Infinity » 0^0 equals 1 or undefined? » 2009-02-08 06:16:09

simron wrote:

Google says 0^0 is 1.
Yahoo says 0^0 is 1.
Windows Live Search says 0^0 is 1.
I says 0^0 is 1.

Excel says it's undefined.
TI-83 says it's undefined.
I say I still don't know enough about it to make an educated decision.

#66 Dark Discussions at Cafe Infinity » Googol » 2009-02-06 10:23:06

bossk171
Replies: 1

I'm teaching an accelerated math class of 9 sixth graders. Today we talked a little bit about googol and googolplex, but I wanted to follow up with something else next week. So i've googled googol and looked at the info, but I can't find anything about practical or mathematical applications.

Does googol have a purpose or is it just interesting because it's so big? It seems odd that in popular culture it's better known than e but has less of an impact on mathematics and the world in general.

So I guess my question is, "why do I care about googol?"

#67 Re: Dark Discussions at Cafe Infinity » 0^0 equals 1 or undefined? » 2009-02-06 03:32:57

JaneFairfax wrote:

So do you now see the flaw (in both “proofs”)?

I see that there is a flaw, but I'm not sure what. If I had to guess, I'd say it's the divide by zero flaw, but which step specifically is the no-no? Is it 0^0 = 0^(1-1) step? I'm not sure why, but I think it is.

And surely 1 does equal x/x so what is the actually flaw? Like I said, I get that there is one, I just can't tell what it is specifically.

#68 Re: Dark Discussions at Cafe Infinity » 0^0 equals 1 or undefined? » 2009-02-06 03:05:48

Doesn't 0^0 = 0/0?

I suspect that this is one of the proofs with a fundamental flaw (like the proof 1=2) but where is the flaw? Is it as simple as dividing by 0?

To me this says: 0^0 is undefined because 0/0 is undefined.

What is complex analysis? Is it simply analyzing complex functions the Reinman Hypothesis? Or does it mean something else?

#69 Re: This is Cool » Lockhart's Lament » 2009-02-03 12:52:58

I agree 100% with that, MathsIsFun. I told the kids that I will always make my best effort to use the right terminology, but that they should be more concerned with conceptualization than terminology.

#70 Re: This is Cool » Lockhart's Lament » 2009-02-03 02:35:37

My essay isn't very good, I'm not a very good writer (which is why I frequent Math-Is-Fun forums and not Boring-essays-that-I-have-to-write-because-my-English-teacher-told-me-so-and-I-just-want-to-get-through-English-101-so-can-eventually-graduate-and-get-a-good-job forums).

If it were about math I'd definitely post it here for some feedback, but it's just about product placement so I don't think it'll interest anyone.

I see what you're saying about throwing out the baby with the bathwater,  my biggest concern is with the de-emphasis on terminology. It might be boring to learn the vocab, but necessary for communicating your findings and interacting with others. I just started an accelerated math club of sorts at my local elementary school with nine 6th graders. I'd like to do exactly what this paper describes only we will be saying "tetrahedron" instead of "triangle thingies" Using correct terminology allows you work together to find solutions and that is essential to any exploratory math course. We won't, however, be taking vocab quizzes or anything ultra-lame like that.

#71 Re: This is Cool » Lockhart's Lament » 2009-02-02 12:47:53

In my English 101 class I had to write an expository essay about anything I wanted (first draft due today) I sat down to start writing about fundamental flaws in mathematics education today. I quickly realized that I'm not a good enough to express everything I wanted to express about the subject and I opted to write about the disturbing role product placement plays in today's media.

After putting my finishing touches on my first draft last night, I checked this forum to see if I'd missed anything interesting and imagine how shocked I was to read exactly the essay I wanted to write. Absolutely phenomenal I printed it out and read it and was impressed by every word of it.

Just curious MathsIsFun, what parts didn't you agree with?

#72 Re: Help Me ! » x^n + y^n = 1 » 2009-01-01 10:21:00

Are you trying to differentiate:

With respect to x with n as a constant? If so it's something like:

Which can be confirmed with this site: http://calc101.com/webMathematica/derivatives.jsp

(I did it long hand before cheating though)

The integral is way over my head and it involves a function I've never heard of called the hypergeometric function: http://integrals.wolfram.com/index.jsp? … ndom=false

If that's not what you were looking for, sorry. I really hope that someone much smarter than I (which is most people here) might get involved and work some calculus magic.

Also it would be great if a mod moved this to Euler Avenue.

#73 Re: Help Me ! » x^n + y^n = 1 » 2008-12-29 14:41:56

I've spent at least an hour working on this and I've accomplished: nothing.

I wanted to isolate n so that some function N could be written in terms of x and why and then set N(x,y) = z and graph N(x,y) in three dimensions. If it's possible to isolate n, then it's well beyond my abilities (which isn't saying much). But I'm very much interested in where this might lead.

random_fruit, look into a freeware program called graphcalc (http://www.graphcalc.com/) you can graph functions pretty easily with it.

Might this be better suited in Euler's Avenue or Cafe Infinity?

#75 Re: Dark Discussions at Cafe Infinity » Why is it that teachers keep insisting that 1 is a prime number? » 2008-12-18 18:27:58

Thanks RaelImperialAerosolKid, and you're right. Like I said, I approached her in private, but it was really awkward for me. I'm try to play the long game here. There's a potential for me to get my own group of advanced kids twice a week and I'm afraid that if I step on any toes this won't happen. Is it fair to lose a battle to win the war? I feel that if I got my own group, I'd be able to make a really big difference, I try to take things on a case to case basis.

Today she told the kids that the 9/11 tragedy happened in 2002, and I did correct her. I'm starting to find my voice.

Board footer

Powered by FluxBB