digg

Join DiggAbout

Donkeys and Elephants and Delegates,oh my!
Check out the most popular Elections 2008 content on Digg.

Math for Geniuses

immense-world.blogspot.com — Simply amazing.

Bury
show profanity settings
expand all
  • newtechfool, on 10/12/2007, -3/+36Aaaah this takes me back to high school. I even recognize some of the teachers coments :-)
    • gosix, on 10/12/2007, -3/+78Peter?
    • rgaane, on 10/12/2007, -19/+4well.. in a way, they were right... i failed math.
    • kingfoot, on 10/12/2007, -0/+34man that was great. i especially loved the infinity/5 one :P
    • Kranklin, on 10/12/2007, -20/+1Yeah, my Teacher did the 8/5 example the other day, man those problems are easy
  • tetsuwan, on 10/12/2007, -37/+1This link does not work.
  • royall64, on 10/12/2007, -14/+24Old, and duped, but still a classic.
  • kingkilr, on 10/12/2007, -43/+1More like math for morons.
    • chris9902, on 10/12/2007, -28/+4yeah those "morons" with an IQ of 254.
    • CaptainWeasel, on 10/12/2007, -0/+27I think I am going to put you into the "Sarcasm for Genious Diggers" post. :)
    • theBrink, on 10/12/2007, -3/+10that's the easy way to find X, Brilliant!
  • remotecontempt, on 10/12/2007, -2/+28Number 5 is pretty clever.
  • bobgb4, on 10/12/2007, -13/+2funny
  • e2superman, on 10/12/2007, -21/+8really could be negative infinity if you assume it converges from the left (increasing to 8). Depends on what direction the limit converges from....
    • dbug, on 10/12/2007, -4/+13This sounds interesting, please tell us more!
    • tuna1, on 10/12/2007, -7/+11Calc sucks, I forbid you to discuss anymore limits.
    • Kranklin, on 10/12/2007, -2/+3Exactly what i thought
    • greyfade, on 10/12/2007, -7/+2it approaches negative infinity (it does not converge! by definition!) iff the limit is negative.
    • paw09, on 10/12/2007, -5/+0Isn't it undefined?
    • D4r7h3v1l, on 10/12/2007, -9/+4There is no limit at x=8. It does not exist. If it was lim(x->8)1/(x^2-8), then infinity would be correct.
    • aprocter, on 10/12/2007, -9/+1who gives a *****?
    • simX, on 10/12/2007, -3/+11@D4r7h3v1l: Agreed, the equation is actually wrong. There is no limit at x=8, since it simultaneously approaches both infinity (from the positive direction) and negative infinity (from the negative direction). The definition of a limit stipulates that the limit must be the same when approaching from either side.
    • FluffyArmada, on 10/12/2007, -0/+11Calculus, because 7 plagues and a flood weren't bad enough. 
    • SqueakyMouse, on 10/12/2007, -0/+1It depends which metric space you're working over. If you're working over the reals with the euclidean metric, then the limit does not exist as some of have correctly pointed out (the right and left limits exist in the extended reals and are different). If you're working over the interval [8,10] (for example), with the same metric, then the function tends to infinity as described in the article.

      If the student was so dumb he put the 5 on its side though, they were working over the reals in both cases (for simplicity), making the teacher wrong.
  • Bob042, on 10/12/2007, -2/+11Reminds me of the proof that (fill in the blank)=Evil.

    Doesn't translate to type well, but google girls=evil for an example.
  • u8myfoood, on 10/12/2007, -0/+15my math teacher would kill me if i tried that!
  • sinnerman, on 10/12/2007, -6/+1Funny, but several of these look very contrived to me. I doubt those ones real examples of student work.
  • TwoD, on 10/12/2007, -0/+5That was just so funny. Those kids have some imagination. It must be great to be a teacher when you see this, it just makes your day.
  • knoware, on 10/12/2007, -16/+2SAY WHAT?
    • seventoes, on 10/12/2007, -0/+22TURN ON YOUR HEARING AIDS, GRANDPA.
  • tthomas1529, on 10/12/2007, -1/+10big deal, i found x
  • sansmatthew, on 10/12/2007, -0/+14haha. that was great. Love the sideways 5.
  • estacado, on 10/12/2007, -0/+9It's been a while since something actually funny came up on Digg. Good find.
  • ssergei, on 10/12/2007, -0/+8man, if i were the teacher i would have given him the find "x" question. He did exactly what it asked to :P
  • Daiken, on 10/12/2007, -8/+2You have to remember, there's no way to verify which one of these were actually made by a student. If anything, maybe the first one imo seems real. The others could have just been made up. I've seen several of them before on the net.
    • hammydude, on 10/12/2007, -0/+18Who cares? They are pretty funny, that is all that matters. I am sure that at least half of the story-jokes are not even real.
  • chicken101, on 10/12/2007, -0/+11Number five made me choke on my food. Priceless.
    • SourWorm, on 10/12/2007, -0/+15No eating or drinking at the computer. That is all.
  • ninjaX14, on 10/12/2007, -9/+3the limit examples are totally wrong....can someone prove me wrong???as x goes to 8 or 5 and the equation in the denominator is x-8 or x-5 wouldn't that make the fraction undefined (you cant have a zero in the denominator, that's just obvious) now can someone prove me wrong OR is it has it approaches 8 or 5 it never gets close to 8 making it 7.99999999-8.making it the smallest number possible....but not zero

    prove me wrong...
    • mathmanjeffy, on 10/12/2007, -0/+8As you approach 8 your number in the denominator gets really really really small. 1 / a really really really really really small number = a really really really really really big number.

      It approaches 8, it never reaches 8, so you aren't dividing by zero.

      That's the "I'll argue against everything I think is wrong" dumbed down version of the proof. See a gradeschool textbook for more information.
    • bluechocobo42, on 10/12/2007, -0/+6 Indeed the function as defined (lim x->8 1/(x-8)) is undefined. However, the concept of a limit is that while x will become VERY close to 8, it will never become 8, as you said "has it approaches 8 or 5 but it never gets close to 8 making it 7.99999999-8. making it the smallest number possible, but not zero". This allows one to evaluate undefined functions such as 1/(x-8) | x = 8.

      If the limit had instead said x->8+, which means that x is approaching x from the right (as in, coming from 9), the function will approach infinity. If the limit had said x->8-, which means that x is approaching x from the left (as in, coming from 7), then the function will approach negative infinity.

      Edit: Bah, Mathmanjeffy beat me while I was typing. Grrr.
    • dallen, on 10/12/2007, -0/+3The number in the denominator only approaches zero. And as y gets tinier and tinier 1/y approaches infinity. Graph it for smaller and smaller values of y and you'll see that your line goes to infinity. Check out a pre-cal site and they'll have a better explanation of it

      edit: I see I was very late. Need to refresh more often.
    • seventoes, on 10/12/2007, -1/+8Thats all wrong. The Retro-Encabulator needs relative motion of conductors and fluxes in order to properly operate. Also, modial interaction of magneto-reluctance and capacitive diractance need to be unilateraly phased to correctly synchronize cardinal grammeters.

      http://youtube.com/watch?v=PtuqjFf7-N4
  • chuckwoolery, on 10/12/2007, -0/+15# 3 reminds me of a calculus test I took in High School.

    The question stated:
    Show that [integral] sin(x) dx = -cos(x) + C

    So, I went on to show that d(-cos(x) + C)/dx = sin (x)
    thus showing [integral] sin(x) dx = -cos(x) + C by the Fundamental Theory of Calculus

    The teacher gave me 0/10 because he wanted me to show the steps in the other direction. I honestly was not trying to get out of answering the question, it just seemed to me the obvious way of answering it. This page http://math2.org/math/integrals/more/restrig.htm seems to agree with me.

    I'm still bitter.
    • RandomGuySteve, on 10/12/2007, -7/+3It sounds like you learned a valuable lesson. You went around the hoop you were supposed to jump through, and you didn't get your reward like you hoped.

      Thats life, for the most part. Until you become the one giving the rewards and holding the hoop, of course.

      The comments on the site really bug me. One person mentions that she's an engineer and the rest act like 12 year olds accusing the girl of saying that being an engineer was a requirement to find the Math funny.

      Then I realise that pretty much everyone acts 12 when they have a shield to hide behind. Just look at drivers.
    • rparle, on 10/12/2007, -0/+10Sounds like my school years. I wasted so much energy fuming about teachers not giving me proper credit for correct answers because I had given what they asked for rather than what they wanted. You occasionally get teachers who appreciate your unexpected solutions, and it can be really fun to work with them. I once had a teacher who gave rewards for finding shortcuts in maths problems.
    • itistoday, on 10/12/2007, -2/+1@chuckwoolery:

      That makes me respect your teacher. From what you've said it seems like he/she was actually trying to get you to prove that equation. You're right though, normally most teachers (*cough*bad ones*cough*) will do exactly what you did, but you have to see that what you did was circular reasoning, and not actually showing *why* the integral of sin(x) is -cos(x) + C.

      To be honest, however, that seems like a tough question and I'm surprised your high school teacher asked you that. I'm not really sure how you'd go about proving that mathematically, anyone know? If you can prove *why* the derivative of sin(x) is cos(x) then that's your answer.

      The only thing I can think of doing is taking the limit of h as it goes to zero:

      lim h->0 [ ( sin(x+h) - sin(x) ) / h ]

      The farthest I can get with that is:
      lim h->0 [ (cos(x)-sin(x))/h ]

      ???
    • itistoday, on 10/12/2007, -2/+1@chuckwoolery:

      BTW, forgive me if I misunderstood what your teacher was trying to get you to do. Was he/she just telling you to literally reverse the steps you showed on paper? Because if that's the case then they really are a douchebag.

      Edit: as for the proof... perhaps you have to deal with the taylor expansion of sin(x)? Or one of the "reiman sums"? *****, I'm forgetting all this...
    • ja1217, on 10/12/2007, -2/+2@RandomGuySteve

      12 sounds a little old for most drivers. I'd say they have the tempers of 2-3 years old, while all of the old drivers have the same coordination level of 2-3 year olds as well.
    • babayada, on 10/12/2007, -2/+2I believe you have every right to feel bitter.

      You demonstrated an ability to solve the problem, and it sounds like you found a superior way. I think the educational system is far too rigid and that methods that they use are better for creating unthinking zombies who can do various tasks (robots) than thinking individuals.

      Tests are intended to make the students demonstrate specific skills. From a perspective, you failed because you failed to demonstrate the specific ability the teacher desired to see. Perhaps the teacher failed in communicating this or perhaps you failed in understanding his or her intention.

      In any case, if your answer was correct you should have been given the opportunity to state your case and then the opportunity to demonstrate you could do it the way you were expected to. But, then, that requires discussion and mutual respect, where the student is treated like a rational, intelligent being.

      From a higher perspective, you were right. You solved the problem in a way you found superior. You simply failed to play the game as the game was intended to be played. You're in good company. You have more in common here with Einstein, who refused to play by the rules and followed what made sense to him, than a robot.

      Obedient students, good boys and girls who only know how to follow directions are never in danger of being creative or genius. I'd say stop being bitter and start being thankful. Under the circumstances, the 0 is a badge to wear proudly. It means you're not one of the living dead.
    • fredricko, on 10/12/2007, -2/+1@Itistoday

      The solution relies in the trig identity sin(a+b) = sin(a)cos(b) + cos(b)sin(a).

      = lim(h->0) ( ( sin(x + h) - sin(x) ) / h )

      = ( ( sin(x)cos(h) + sin(h)cos(x) - sin(x) ) / h )

      = ( ( cos(x)sin(h) + sin(x) ( 1 - cos(h) ) / h )

      = cos(x) lim(h->0) ( sin(h) / h ) - sin(x) lim(h->0) ( 1 - cos(h) ) / h ) )

      By the squeeze therom By L'Hopital's (Lhopeetals) Rule
      = ( cos(x)( 1 ) - sin(x)(0) )

      = cos(x)
    • XAsmodeaNX, on 10/12/2007, -4/+2Your completely wrong. You look bad for being dumb. Next time don't lie about how "good" at math you are.

      It's sin(a+b) = sin(a)cos(b) + sin(b)cos(a)

    • RandallBe, on 10/12/2007, -1/+2@XAsmodeaNX
      Putting down others and trolling is a sign of unintelligent. please next time you thing about posting don't. also calling someone wrong when they are right is stupid, next time before you talk about something know what you are talking about.
    • itistoday, on 10/12/2007, -0/+1@fredricko:

      Yes, that's what I was trying to use, but I don't see how you make this step:

      = ( ( sin(x)cos(h) + sin(h)cos(x) - sin(x) ) / h )
      = ( ( cos(x)sin(h) + sin(x) ( 1 - cos(h) ) / h )

      It seems to me you factored that last part incorrectly, shouldn't it be:

      = ( ( cos(x)sin(h) + sin(x) ( cos(h) - 1 ) ) / h )

      ?
    • SEMW, on 10/12/2007, -0/+1I hate to say this, but chuckwoolery and most people who've replied to this thread are wrong: it *doesn't* always follow that

      integral( f ' (x) dx ) = f(x) + c d/dx f(x) + c = f ' (x)
      ( means "if and only if")

      It *nearly* always follows; and it always follows for polynomials (proven fact). But there are exceptions (e.g. it doesn't work with the step function), and so it isn't a rule you can always safely apply, despite that if no-one's found a counterexample in purely trig equations such as the one chuckwoolery had to use. Since it hasn't been *proven* for non-polynomials, you can't rely on it being true in a proof, even if it always works in practice.

      Although, actually, now I come to think of it, I could be wrong, I think someone might have proved it for trig-only equations. I'd have to check. If that is the case, then I apologise to chucknorris.
    • fredricko, on 10/12/2007, -0/+1@XAsmodeaNX

      Yeah, obvious typo on my part. If you noticed though, I did it correctly two lines down :P Sounds like someone takes his math very seriously.

      @itistoday

      Yeah, you are right too. I probably screwed up when I was re-arranging the terms in my head. I'm not used to typing everything out like this. Good call.
  • Jacobi, on 10/12/2007, -0/+5Real or fake, these made me laugh. I love math humor.
    • FluffyArmada, on 10/12/2007, -0/+1There's a good one, but I can't find it. But what happens is as follows: Frame 1, you see the number 20; Frame 2, you see an explosion; Frame 3, you see two 2s and a five. :)
    • Smwbigboss, on 10/12/2007, -0/+2I know what you're talking about. It's from a web comic, but I forget the name. I think it had something to do with the word bible.
  • jbrevik, on 10/12/2007, -0/+4The answer for the problem "Find X" is absolutely correct. The question should have been "Find the value of x as it relates to the Pythagorean theorem" They should get credit for that question.
    • Beverman, on 10/12/2007, -1/+0Agreed, I wish i had thought of that while i was doing math. I still remember the day my friend put down "Duck liver" for an answer on a test :)
    • mathmanjeffy, on 10/12/2007, -2/+6Find the value of x as it relates to the Pythagorean Theorem is incomplete and inaccurate.

      "Find the value of x as it relates to a special case of the Law of Cosines where the angle opposite the side in question is 90 degrees."

      Unless, of course, this is a state administered exam, in which case the question will be:

      "Find x as it relates to what you had for supper last night."
    • Beverman, on 10/12/2007, -0/+2We always just had "Find the value of x for:" on our tests.
    • dallen, on 10/12/2007, -0/+4My teacher was unimpressed when I answered Mark Twain as the answer to an Algebra problem.
    • davori, on 10/12/2007, -0/+1Find x is completely acceptable, you don't get spoonfed the exact method of finding the answer, anybody of ages 13+ should know how to use pythagoras without even thinking about it, the diagram showed that it was a 90deg angle anyway. :|
    • SEMW, on 10/12/2007, -0/+2I agree with davori. Think about it; if it were otherwise, then hardly any question would be "complete and accurate".
      "Choose one of the following essays" would be satisfied by "I choose number 1".
      "Write down Lenz's law" would be satisfied by " 'Lenz's law' "
      "Expand the following equation" would be satisfied by drawing it stretched parallel to the x-axis, y-axis invarient.
      "Find the answer to..." would be satisfied by "You will find the answer in the answer book".
      Etc, etc.
  • scape, on 10/12/2007, -11/+1I don't get it
    • maehem, on 10/12/2007, -4/+7You must be one of the special kids who ride the short bus and wear a helmet.
  • aacidusX, on 10/12/2007, -1/+3LOL, i was about to get a piece of paper and pencil to do this... low and behold... it was some funny stuff
    • kigabit, on 10/12/2007, -0/+14lo* and behold.

      The More You Know™
    • stlcadet11, on 10/12/2007, -0/+7+ digg to kigabit's comment for the use of the trademark symbol
  • XpLiCiT, on 10/12/2007, -0/+3This is definatly the funniest thing I've seen today. Thanks for the submission. A+ for you. haha
  • babayada, on 10/12/2007, -1/+7It strikes me that all of these answers show very fine examples of lateral thinking, which should be noticed and encouraged in students. While not technically correct, these answers show creativity and the kind of thinking that supposedly Alexander the Great demonstrated when he cut the Gordian Knot. In fact, it's *exactly* the same kind of thinking that the student demonstrated by circling x and writing "there it is" when asked to find it... the same with expanding the problem.

    When I hear people like Richard Feynman say that most people are not taught how to do math, merely engage in processes that allow them to solve problems without thinking, I think of things like this and how original thinking is systematically beaten out of students. I wonder about how I might have been taught math differently. I wonder what being taught the basics of math on up to advanced subjects by a man like Feynman might have been like.

    These answers are funny, I think, because they do represent a kind of genius. If they were *simply* wrong, they wouldn't make us laugh.
    • usherzx, on 10/12/2007, -0/+1wow you're right
      never thought of it like that
      sweeeet
  • bpnoy, on 10/12/2007, -4/+3i think we shouldn't be making fun of them. they might not be good in math but i'm sure they are very good in something else.
  • DyCyn, on 10/12/2007, -0/+7One of my favourites: http://www.fileden.com/public/2006/7/16/44ba07bcbeb5f553211186.gif
  • charlemagn3, on 10/12/2007, -0/+0Ah man that was great. Almost inspires me to do something dumb on the next ap calc test.
  • hopstah, on 10/12/2007, -0/+0anybody else notice that the second example is wrong? the first part actually equals negative infinity
    • imikedaman, on 10/12/2007, -0/+1No, the function is undefined because the limit is different on either side of 8.
    • Scagli3tti, on 10/12/2007, -0/+2For the last time, if the limit as x approaches a value from the left does not equal the limit as x approaches that same value from the right, the limit is undefined.

      http://i61.photobucket.com/albums/h48/Scagli3tti/DiggCalc.jpg

      As x approaches 8 from the left, y goes to negative infinity. As x approaches 8 from the right, y goes to infinity. Therefore, limx->8 1/(x-8) is undefined.

      Now stop looking so deep into a joke and enjoy the article.

  • ffachopper, on 10/12/2007, -1/+1amazing! i laughed a lot with it, dugged!
  • rowlodge, on 10/12/2007, -1/+03 rubber duckies, take 1 rubber duckie get ummmm..
  • computermatt, on 10/12/2007, -1/+2Here it is!
  • Recuso, on 10/12/2007, -2/+0As some others mentioned, Lim (1/x-8) as x approaches 8 is undefined, not infiniti. Confirm this on any Ti-89: limit(1/(x-8(,x,8) and you will get undefined. You are often able to evaluate limits simply by plugging in the number listed for x. 1/8-8 = 1/0 == undefined.

    Still a funny page, though =)
  • bluephoenix, on 10/12/2007, -0/+1yep...it's almost getting to the point where I'll stop coming here. This is atrocious that this made front page...again.........
  • madc0w, on 10/12/2007, -0/+1http://www.duggmirror.com
  • sivatalla, on 10/12/2007, -0/+0Nice...

  • rebz, on 10/12/2007, -0/+1http://duggmirror.com
  •  

    Login or register to add a comment

    Create a new account or login to join in the conversation on Digg. You'll also be able to Digg stories to help promote things you like.


© Digg Inc. 2008 — Content posted by Digg users is dedicated to the public domain.
DIGG, DIGG IT, DUGG, DIGG THIS, Digg graphics, logos, designs, page headers, button icons, scripts, and other service names are the trademarks of Digg Inc.