Search found 119 matches

Thu Oct 30, 2014 8:40 pm UTC
Forum: Logic Puzzles
Topic: Two guards, two doors, no instructions
Replies: 63
Views: 17296

Re: Two guards, two doors, no instructions

With Xeno's solution, I have one question. How would you know they are not both liars? Both guards say the 'situation' (The guards say 1 is a liar, 1 always tells the truth, and only 1 door leads to freedom). That statement itself could be false because then if you do ask a guard, they can say a dif...
Thu Mar 13, 2014 7:48 pm UTC
Forum: Mathematics
Topic: negative 0
Replies: 6
Views: 3067

Re: negative 0

snowyowl wrote:If f has a limit of 0, then 1/f has a limit of infinity.

*When f approaches 0 from the positive side
Fri Jan 10, 2014 8:11 pm UTC
Forum: Science
Topic: Do cold drinks affect coughing?
Replies: 13
Views: 69043

Re: Do cold drinks affect coughing?

It could just be a cultural lore kind of thing.

It's like Serbians and promaja (draft). Doesn't matter if you're in a hot stuffy crammed bus, don't you dare open a window.
(This has brought up interesting arguments in my childhood. I never understood the superstition.)
Sun Aug 25, 2013 2:06 pm UTC
Forum: Logic Puzzles
Topic: Logic Puzzles on Sporcle
Replies: 6
Views: 5433

Re: Logic Puzzles on Sporcle

jestingrabbit wrote:Or, you know, a bookmark.

Well I'm wondering more how new users would discover this forum. Bookmark works fine once you've already discovered it.
Mon Aug 19, 2013 4:30 am UTC
Forum: Logic Puzzles
Topic: Logic Puzzles on Sporcle
Replies: 6
Views: 5433

Logic Puzzles on Sporcle

Hi everyone, I used to lurk the logic puzzle forum a lot a couple of years ago and I always enjoyed going over the puzzles here (even though a lot of them just flew over my head!). Anyway, if anyone has heard of Sporcle, it is a quiz/trivia site. The site has a subcategory for logic puzzles, that I ...
Mon Oct 15, 2012 6:28 am UTC
Forum: Mathematics
Topic: Why is calculus such a big deal?
Replies: 11
Views: 3457

Re: Why is calculus such a big deal?

Insurance and life-tables are huge applications of calculus. Risk and money should be something interesting for someone working in a business degree. Although a good amount of Actuarial Science is necessary to know the stuff but I think showing some life tables would do fine. The calculus is more in...
Fri May 04, 2012 2:03 am UTC
Forum: Mathematics
Topic: For the love of god help.
Replies: 8
Views: 2319

Re: For the love of god help.

gmalivuk wrote:Note that this looks homework-like, so let's let the OP come back with something more before offering any more explicit solutions.

Ah sorry. You're on the ball, I couldn't even edit my post (sorry slow realization on my part).
Tue Mar 27, 2012 6:43 am UTC
Forum: Mathematics
Topic: Finding the probability of a probability being at least 0.75
Replies: 12
Views: 2918

Re: Finding the probability of a probability being at least

The second thing is that there is no "probability of x being higher than 75%". x is a fixed, but unknown value, not a distribution. Talking about probabilities doesn't make much sense in that matter, which is part of the reason you couldn't make sense out of it. The statement is ill-defin...
Fri Mar 16, 2012 12:52 am UTC
Forum: Mathematics
Topic: An easier math(s) puzzle . . .
Replies: 20
Views: 5509

Re: An easier math(s) puzzle . . .

General Solution for f(n, n+1, ?) = 1:
Spoiler:
((n +1) - n) ^ ?
Fri Mar 09, 2012 10:18 pm UTC
Forum: Mathematics
Replies: 40
Views: 7629

No, then you don't have a probability distribution at all. Any distribution MUST have a bias, some integers are more likely than others. Any continuous pdf has the property that the probability of any particular number is 0. In this case, we are dealing with something that is discrete, but there ar...
Fri Mar 09, 2012 9:46 pm UTC
Forum: Mathematics
Replies: 40
Views: 7629

The probability of getting each integer is 0 (any number above 0 is too high). It seems that the probability would be "one in infinity", since there is one integer which is the same out of an infinite number of possible integers. But isn't that probability equal to zero? And if it's zero, ...
Wed Feb 01, 2012 6:16 am UTC
Forum: Mathematics
Topic: An interesting probability problem that I thought of
Replies: 5
Views: 1287

Re: An interesting probability problem that I thought of

The number of cards doesn't exactly matter in this situation (well it does, but only for determining the probability of getting all the cards). There's a simple way of doing this: Just look at the cards that are important to you. That is, the ones that need to be looked at to have a specified number...
Thu Dec 08, 2011 6:48 pm UTC
Forum: Mathematics
Topic: Labyrinth Puzzle
Replies: 15
Views: 3462

Re: Labyrinth Puzzle

If a guard definitely either always tells the truth or always tells a lie, then you can ask them "If I was to ask you '<question>', would you answer 'Yes'?" to get a truthful answer to a question. Then it's just a case of binary searching. Note that with n doors you can't do better than a...
Thu Dec 08, 2011 6:38 am UTC
Forum: Mathematics
Topic: Labyrinth Puzzle
Replies: 15
Views: 3462

Re: Labyrinth Puzzle

I'm assuming there's always only one door that leads to freedom. First we don't know how many guards tell the truth and how many don't lie. But it doesn't really matter since now we only need to ask 1 guard. We go to 1 guard and ask if one door contains freedom, and then if the other door contains f...
Wed Dec 07, 2011 5:35 am UTC
Forum: Mathematics
Topic: x(x+1) =/= y(y+2)?
Replies: 13
Views: 2731

Re: x(x+1) =/= y(y+2)?

Nevermind, silly question.
Wed Nov 16, 2011 6:44 am UTC
Forum: Mathematics
Topic: Help Me Understand?
Replies: 6
Views: 1512

Re: Help Me Understand?

Isn't this a counter example?:

Say the numbers on apples {1, 1, 2}, and on oranges {1, 2} (each number representing the number written on the fruit). There are two unique apples and two unique oranges, but there are more apples than oranges
Sat Nov 05, 2011 5:13 am UTC
Forum: Mathematics
Topic: Interesting problems which require the triangle inequality
Replies: 10
Views: 2445

Re: Interesting problems which require the triangle inequali

Maybe I'm missing something, but I'm as impressed by the fact that walking around two sides of a triangle takes longer than walking along one as by the fact that 3 is greater than 2.
Tue Nov 01, 2011 7:38 am UTC
Forum: Mathematics
Topic: Self-referential probability questions
Replies: 16
Views: 4411

Re: Statistics problem

None of the questions are correct, so 0%. 0% isn't an option so it's true.
Fri Oct 07, 2011 3:53 am UTC
Forum: Mathematics
Topic: Mathematical Induction
Replies: 47
Views: 6424

Re: Mathematical Induction

@Deveno
Don't confuse mathematical induction with inductive reasoning. Mathematical induction is actually deductive reasoning.
Fri Sep 30, 2011 5:54 am UTC
Forum: Mathematics
Topic: Mathematical Induction
Replies: 47
Views: 6424

Re: Mathematical Induction

skullturf wrote:You can start any proof you like by just ASSUMING some statement P is true.

I got into some trouble from my prof for this telling, me you don't assume statement P is true, you assume the variable makes P true
Fri Aug 26, 2011 2:41 am UTC
Forum: Mathematics
Topic: Dumb statistical analysis query (90% analysis)
Replies: 6
Views: 1432

Re: Dumb statistical analysis query (90% analysis)

So the first table, X represents the percentage breakdown of each category voting for X (which must add to 100%), while in the second table, we're looking at the percentage in the group that voted for X. I'm assuming this, and that you want to know why X is different between the two tables. If I'm w...
Fri Aug 19, 2011 12:21 am UTC
Forum: School
Replies: 16
Views: 3947

Here's my thoughts. First off, I highly recommend NOT going to UofT (I know you didn't bring it up but it was mentioned in a post so I figured I'd mention it). Besides how tough it is to get scholarships there, their reputation comes almost entirely out of research and graduate studies. At an underg...
Wed Aug 03, 2011 6:52 pm UTC
Forum: Mathematics
Topic: Minesweeper question
Replies: 9
Views: 2001

Re: Minesweeper question

The Vista one is programmed so that you always get a blob on the first turn. I hate it because it feels like they're just making it easier for you. It also highly increases the chances of winning in beginner on the first click. If you want to play real minesweaper, then find one online or on Windows...
Wed Aug 03, 2011 5:13 am UTC
Forum: Mathematics
Topic: Winning bids -am i right?
Replies: 8
Views: 1490

Re: Winning bids -am i right?

wait.... is the answer for C just .25? Since A and B are independent so the probability of B never changes regardless whether A is won or not...? What you're saying is true, if it was independent. But think about it, if it was independent, then winning both is .6 * .25 = .15. But the question speci...
Wed Aug 03, 2011 4:39 am UTC
Forum: Mathematics
Topic: Winning bids -am i right?
Replies: 8
Views: 1490

Re: Winning bids -am i right?

What I like to do when I tutor people about this is to always draw a venn diagram. It makes visualizing it much easier. When you have "What's the chance of winning B if you won A", just focus on the A circle and see what percentage of it overlaps with B
Wed Aug 03, 2011 4:02 am UTC
Forum: Mathematics
Topic: Minesweeper question
Replies: 9
Views: 2001

Re: Minesweeper question

To summarize, there are 81 spots, where 10 are mines, and 71 are not. In a corner, it is pretty easy, since we only have to worry about 3 spots, and just worry about 1 or 3 mines. P(1 mine) = (10/81)(71/80)(70/79) * 3 P(3 mines) = (10/81)(9/80)(8/79) Just add the probabilities up. Edit: Answer is: P...
Tue Aug 02, 2011 3:56 pm UTC
Forum: Science
Topic: Yay, determinism! (Silly philosophical question)
Replies: 16
Views: 2290

Re: Yay, determinism! (Silly philosophical question)

Is it not possible for the machine to enter it's own loop that would predict the future correctly? As in the machine already has determined that the person will look at the machine and the future will happen as 'determined', even though the person is aware of what will happen. Basically, instead of ...
Thu Jul 28, 2011 4:20 am UTC
Forum: Mathematics
Topic: "Most Common" Numbers
Replies: 5
Views: 1631

Re: "Most Common" Numbers

I believe you're asking about this http://en.wikipedia.org/wiki/Benford's_law If data was falsely created randomly, the probability that the first digit is a certain number will be 1/9 (0 can't be the first digit), and 10% for any digit after the first. However real world observations don't have a u...
Tue Jul 26, 2011 7:44 pm UTC
Forum: School
Topic: Finding people with similar interests
Replies: 25
Views: 4164

Re: Finding people with similar interests

You know what, I bet people are just put off by your attitude.
Tue Jul 26, 2011 4:19 am UTC
Forum: School
Topic: Finding people with similar interests
Replies: 25
Views: 4164

Re: Finding people with similar interests

I would like to just avoid small talk (which I find mentally exhausting to the point where I can't function for the rest of the day). I think this is the main problem. You want to meet new people, but small-talk is usually what happens when you first talk to someone you don't know. It's usually fro...
Sat Jul 23, 2011 9:14 pm UTC
Forum: Mathematics
Topic: p-value?
Replies: 5
Views: 1577

Re: p-value?

Fri Jul 22, 2011 3:58 am UTC
Forum: Language/Linguistics
Topic: !? or ?!
Replies: 30
Views: 3964

Re: !? or ?!

I use both. I just put the more important one first (the one with more emphasis) and that depends on context. E.g. "What did you say!?" is more of a reaction and rhetorical question. I knew what was said. Really, I want to say "What did you say!", but it is still technically a qu...
Wed Jul 20, 2011 8:30 pm UTC
Forum: Language/Linguistics
Topic: Sentence construction challenge
Replies: 33
Views: 5815

Re: Sentance construction challenge

I doubt there is some combination of x's that will have a unique solution.

scratch123 wrote:xxx xxxx xxx xxxxxx xx xxx.

Another solution: The ball can bounce on him.
Mon Jul 11, 2011 4:30 am UTC
Forum: Language/Linguistics
Topic: An experiment, if you don't mind.
Replies: 28
Views: 5881

Re: An experiment, if you don't mind.

Pm'd. I'm also looking forward to the results
Tue Jul 05, 2011 3:48 am UTC
Forum: Science
Topic: Shaking apartment
Replies: 5
Views: 3078

Re: Shaking apartment

I think it's just that the apartment itself shakes (much more than the solid ground), so you will feel the ground beneath your feet shake more when you're in your apartment. Kind of like if you try to stay balanced on a carpet while someone is moving it randomly; it's easier to balance standing on t...
Fri Jun 24, 2011 9:29 pm UTC
Forum: Mathematics
Topic: How practical is a B.S. in Math?
Replies: 20
Views: 7781

Re: How practical is a B.S. in Math?

There's a joke around my area that engineering is a blue-collar white-collar job. Pretty much that it's a white-collar job with the pay of a blue-collar job. Also, I enjoy this short clip http://www.youtube.com/watch?v=qOtoujYOWw0 Anyways, I recommend a stats and math double major. It can lead you t...
Fri Jun 10, 2011 7:15 am UTC
Forum: School
Topic: So, I've obtained \$200 for college
Replies: 26
Views: 5370

Re: So, I've obtained \$200 for college

Buy books second-hand whenever you can. You'll save lots of money that way. Also if you don't already have one, get a white board. I found it to be the most useful thing to have, especially when living with other people. If you're going to live on campus residence, some stuff you should get: - cards...
Mon May 30, 2011 8:30 pm UTC
Forum: Mathematics
Topic: alternative mathematics
Replies: 128
Views: 15282

Re: alternative mathematics

So 314man is or has access to someone fluent in Serbian? Was the half-gibberish 314man mentioned from the paper or plain conversation? If it was the paper, this process will become a lot easier if someone communicates with him one on one in Serbian. If his normal writing is gibberish, and he cannot...
Sat May 28, 2011 1:08 am UTC
Forum: Mathematics
Topic: alternative mathematics
Replies: 128
Views: 15282

Re: alternative mathematics

Yup. His grammar in serbian is actually just as bad as you see it here in english. When my friend and I translated it, I got the words right (natural line instead of natural along), and I filled in some grammar holes. I'm actually still confused with "Capital letters for points, the small lette...
Fri May 27, 2011 4:25 am UTC
Forum: Mathematics
Topic: A criminal hides in a room with 99 innocent people...
Replies: 13
Views: 4489

Re: A criminal hides in a room with 99 innocent people...

You have a lie detector that correctly classifies 95% of people As skeptical scientist already said, this is a rather ambiguous statement. He solved it assuming it meant that it always classifies 95% of the people correctly. However if you meant that it classifies a person correctly 95% of the time...