Search found 732 matches

by the tree
Thu Apr 01, 2010 1:12 pm UTC
Forum: Mathematics
Topic: This Can't Be Right
Replies: 8
Views: 1397

Re: This Can't Be Right

But I will note that 1 is an integer, whereas 1.00000... is a real number. Sure, we can say they have the same value, but they are members of different sets. To justify making such a comparison, we really need to show how the integers are embedded in the reals. Yeeeaaaaaaaaahno, For most purposes, ...
by the tree
Thu Apr 01, 2010 1:09 pm UTC
Forum: Mathematics
Topic: Ideal Currency Denominations
Replies: 47
Views: 5812

Re: Ideal Currency Denominations

Is it common all over the US for prices to be [nice, round number] + [weird tax percent], or only in certain states/types of store? Is this a common method in many other countries? Yeah, the big problem is that the sales tax level is very fragmented, totally different between states and IME often d...
by the tree
Tue Mar 30, 2010 10:30 am UTC
Forum: Mathematics
Topic: Math Reference book for Calc and below
Replies: 18
Views: 1581

Re: Math Reference book for Calc and below

I still stand by my recommendation of Calculus: One and Several Variables, but if you're ultimately just looking for reference material rather than something to learn from then that is kind of what the Internet is good at.
by the tree
Fri Mar 26, 2010 11:29 am UTC
Forum: Mathematics
Topic: Math Reference book for Calc and below
Replies: 18
Views: 1581

Re: Math Reference book for Calc and below

FUN FACT: whenever anything is called [subject][number], no-one has any idea what you're talking about. The curriculum varies massively over every school ever. Anyway, if you're looking for a big book to cover most everything, Calc \mbox{u} lus One And Several Variables published by Wiley basically ...
by the tree
Wed Mar 24, 2010 1:39 pm UTC
Forum: Mathematics
Topic: Minimisation, ordering and xkcd#173
Replies: 9
Views: 1852

Minimisation, ordering and xkcd#173

Okay I've searched around in the maths forum for a serious look at xkcd#173 , but I couldn't find anything. I was recently reminded of it because of this blog post which is more or less a simplified version of the same thing. The way I figured the problem should go is that there is a bunch of vertic...
by the tree
Wed Mar 24, 2010 1:03 pm UTC
Forum: Mathematics
Topic: Need a math topic idea
Replies: 8
Views: 947

Re: Need a math topic idea

Is your aim to write about maths, or to write about something that you're applying maths to? Given the choice I'd certainly go for the latter but still involve well written mathematics. Quite how much do you even know? Are you comfortable with differential equations or do you want to stick to straig...
by the tree
Wed Mar 24, 2010 12:52 am UTC
Forum: Mathematics
Topic: Need a math topic idea
Replies: 8
Views: 947

Re: Need a math topic idea

Population modelling isn't a bad topic to write about. For an overly simplistic model of a single population you could say the the birthrate and deathrate are directly proportional to the current population. i.e. \frac{dP}{dt} = (b-d)P \; | b,d \in ( 0 , 1) . Describe what happens bo...
by the tree
Tue Mar 23, 2010 12:47 pm UTC
Forum: Mathematics
Topic: So, my dad sent me 30 dollars
Replies: 17
Views: 3119

Re: So, my dad sent me 30 dollars

The Pleasures Of Counting is a good insight into what the hell applied maths actually is. The Road To Reality is more or less all the mathematical physics that you'll ever really care to know.
by the tree
Sun Mar 21, 2010 12:18 pm UTC
Forum: Mathematics
Topic: HW Help: attractive forces and differential equations.
Replies: 0
Views: 511

HW Help: attractive forces and differential equations.

I'm given a differential equation in terms of u ( \theta ) and F(\cdot) where u=\frac{1}{r} and F is given, so I can get a general solution for u( \theta ) . But the initial conditions that I'm given are in terms of r and the radial and transverse velocities so how can I get ...
by the tree
Wed Mar 03, 2010 2:21 pm UTC
Forum: Mathematics
Topic: Cartesian Product
Replies: 5
Views: 853

Re: Cartesian Product

But that each one had a point (a,b,c,d) with a,b,c,d belonging to R in the one case and with two of the four belonging to R and the other two belonging to the set of imaginary numbers. Not sure how to express the imaginary numbers as a set other than saying they are (-inf*i,inf*i). Well, we're talk...
by the tree
Sun Feb 28, 2010 6:55 pm UTC
Forum: School
Topic: Schools of Fools
Replies: 125
Views: 15056

Re: Schools of Fools

It's also worth noting that the education you receive in school is not just limited to the stuff in the book or coming out of the teacher's mouth. There's lessons to learn about social interaction, social groupings and how other people work. These are just as, if not more, useful than the qualifica...
by the tree
Sun Feb 28, 2010 1:24 pm UTC
Forum: School
Topic: Schools of Fools
Replies: 125
Views: 15056

Re: Schools of Fools

In the United States, schools are mostly stupid. Most people who go to public schools are complete idiots. There are the people care about football and HAIR! There is no way I could make this clear enough - everything that you care about, ever have cared about or ever will care about is no less or ...
by the tree
Wed Feb 24, 2010 9:28 pm UTC
Forum: Mathematics
Topic: Base pi
Replies: 38
Views: 12357

Re: Base pi

What does e look like in base π? Maybe equally, if e and \pi are algebraically independent, one can't really be expressed in terms of the other. But if they are algebraically dependant then it should be a finite expression. Whether or not e and \pi are algebraically independent is an unsolved quest...
by the tree
Wed Feb 24, 2010 6:26 pm UTC
Forum: Mathematics
Topic: I think my Stat prof is nuts
Replies: 11
Views: 1629

Re: I think my Stat prof is nuts

I'm guessing it's what I'd call an assessment, any research technique is okay so long as all the work, answers and calculations are your own.
by the tree
Wed Feb 24, 2010 4:18 pm UTC
Forum: Mathematics
Topic: I think my Stat prof is nuts
Replies: 11
Views: 1629

Re: I think my Stat prof is nuts

If it's open book then look for the variance on Wikipedia, you'll find relevant information in the infobox for the the distribution in question.
by the tree
Thu Feb 18, 2010 11:21 am UTC
Forum: Mathematics
Topic: Can't Appreciate the Unknown
Replies: 18
Views: 2278

Re: Can't Appreciate the Unknown

I'd say I was somewhere between 14 and 16 when I learned trig in the geometric sense (just bare definitions), but then learned it all again around 16 in the algebraic sense (identities and stuff). But bearing in mind that American schools seem to teach like, other stuff, I don't see much wrong with ...
by the tree
Tue Feb 16, 2010 1:21 am UTC
Forum: Religious Wars
Topic: religous wars (hipocrites saying we fight for our god)
Replies: 11
Views: 2983

Re: religous wars (hipocrites saying we fight for our god)

it goes against everything that your religion is trying to preach. Not really. Qt preaches that GUI APIs must be sensible, even if they lock out older languages. This is why they use C++ for their API rather than C. Killing people is completely orthogonal to GUI APIs. Qt also preaches "Try rea...
by the tree
Mon Feb 15, 2010 11:53 pm UTC
Forum: Religious Wars
Topic: religous wars (hipocrites saying we fight for our god)
Replies: 11
Views: 2983

Re: religous wars (hipocrites saying we fight for our god)

Voice of reason wrote:rant at me all you want, but your god won't think its right
GaGa says I'm right.
by the tree
Mon Feb 15, 2010 12:31 am UTC
Forum: Mathematics
Topic: HW Help: reciprocal vectors
Replies: 3
Views: 853

Re: HW Help: reciprocal vectors

The course is called Mathematical Modelling, basically all the background knowledge I have for this question is the basics of vectors - dot products, cross products, equations of lines and planes, linear independence, vector spaces, that's probably about it as far as vectors specifically are concern...
by the tree
Sun Feb 14, 2010 6:10 pm UTC
Forum: General
Topic: Lucky Ten Thousand (TIL)
Replies: 13423
Views: 1768116

Re: Today You Learned

the_bandersnatch wrote: his rune was basically a penis:

Image

Pointy.
by the tree
Sun Feb 14, 2010 3:49 pm UTC
Forum: Mathematics
Topic: HW Help: reciprocal vectors
Replies: 3
Views: 853

HW Help: reciprocal vectors

"find the set of vectors reciprocal to the set [this],[that] and [the other]" I'm thinking I must have slept through the class where they explained what those words mean in that context. Google gives me stuff to do with crystallography (wtf?) and latices (which I'm sure aren't something I ...
by the tree
Sat Feb 13, 2010 1:10 am UTC
Forum: General
Topic: Confessional Shed - I'll keep a look-out
Replies: 38049
Views: 2848357

Re: Confessional Shed - I'll keep a look-out

Confession: I want to take the key to that cupboard and throw it in the river, so as you can't get in that cupboard. If I leave the key in my room, you go in to my room and take it. If I leave it in my bag, you go in to my bag and take it. Then you tell me I should hide it better. Thanks, Mum. Take...
by the tree
Fri Feb 12, 2010 8:14 pm UTC
Forum: Food
Topic: Noob Drinks
Replies: 104
Views: 16178

Re: Noob Drinks

Hard cider. If you can't get past the taste of more "serious" seeming drinks and don't want people to htink you're in high school when you're 25, order a Woodchuck or a Hornsby's. Trust me. (That scenario has happened, btw) But... cider makes up a large proportion of what I drank during h...
by the tree
Thu Feb 11, 2010 9:31 pm UTC
Forum: Mathematics
Topic: Wanted to share: 3D Graph Layout Tool
Replies: 3
Views: 1376

Re: Wanted to share: 3D Graph Layout Tool

Okay that looks cool. Can you give a layperson type description on how you decide where to put a node (actually, same question in 2d if that'd lots easier). On an only slightly related related point, trying to look for an IDE that'd help me play I found that there are three languages that could reas...
by the tree
Mon Feb 08, 2010 9:18 am UTC
Forum: Mathematics
Topic: Discrete math shouldnt be this hard, right?
Replies: 20
Views: 4181

Re: Discrete math shouldnt be this hard, right?

I'm currently doing a philosophy course where there's a whole load of logic notation and truth tables and stuff, and apart from the couple of people who've done reasonable amounts of maths or CS, everyone is finding it pretty difficult - so yeah, logic is kind of hard for most people. I don't see an...
by the tree
Wed Feb 03, 2010 11:24 am UTC
Forum: General
Topic: Dear Randall
Replies: 53
Views: 4746

Re: Dear Randall

bigglesworth wrote:I thought they got rid of all the old cloning tanks that had the side effect of making the person gay?
If by gotten rid of you mean I took them all and have them stacked up in my garage, then yes.
by the tree
Tue Feb 02, 2010 2:03 pm UTC
Forum: Mathematics
Topic: Is there a name for this? What about formulae?
Replies: 10
Views: 2044

Re: Is there a name for this? What about formulae?

I'm only in Calc 1 -- what makes it quadratic, not exponential? Exponential means it involves a exponent. Typically e^x (which is called the exponential function) but 2^x is exponential as well (and can be written in terms of the exponential function). Quadratic should be self explanatory. Take a l...
by the tree
Sat Jan 30, 2010 5:42 pm UTC
Forum: Mathematics
Topic: Lowest number spelt with a 'c'
Replies: 12
Views: 5935

Re: Lowest number spelt with a 'c'

One Two Three Four Five Six Seven Eight Nine Alpha Beta Charlie

Two minutes.
by the tree
Fri Jan 29, 2010 5:33 pm UTC
Forum: Mathematics
Topic: Is there a name for this? What about formulae?
Replies: 10
Views: 2044

Re: Is there a name for this? What about formulae?

It seems like you're just looking at series (which are sums of sequences). If you have a sequence \{ a_1 , a_2 , a_3 , \dots \} then the sum of the first n entries would be written as \sum_{i=1}^n a_i (pronounced "the sum of a_i from i=1 to n "). There's lots of standard results for these,...
by the tree
Fri Jan 29, 2010 7:51 am UTC
Forum: Mathematics
Topic: Everyday randomness
Replies: 85
Views: 9568

Re: Everyday randomness

You could, honestly go for a proper pseudorandom number generator and do it with pencil and paper, with a LCG and small co-efficients, a couple of numbers a minute shouldn't be too challenging. Just remember to use a sharp pencil.
by the tree
Fri Jan 29, 2010 12:18 am UTC
Forum: General
Topic: Actual Drnukenness!
Replies: 1358
Views: 345505

Re: I can't believe it is the next day and I'm still DRNUK

I FOUND THE DRUNK THREAD. GO ME. YEAH. I didn't eat much today but I made up for that with lots of Irn Bru and Smirnoff and the season première of Skins so it's all good. Somehow I managed to post something offensive and then the Internet got slightly angry and stuff. Yeah. That. Going back to the d...
by the tree
Thu Jan 28, 2010 11:33 am UTC
Forum: Mathematics
Topic: Probability: Number Guessing
Replies: 15
Views: 3615

Re: Probability: Number Guessing

Going for inclusive - the odds of getting it in n guesses is naively speaking \frac{1}{101} + \frac{1}{100} + \frac{1}{99} + \dots + \frac{1}{101-n} . But as the alt text to 628 points out - people's choice of random number isn't exactly random. Avoid extremes like 0 and 100, and avoid 50 at the cen...
by the tree
Wed Jan 27, 2010 6:07 pm UTC
Forum: General
Topic: Lucky Ten Thousand (TIL)
Replies: 13423
Views: 1768116

Re: Today I Learned

TIL: If I ever go to New York - there is a place I can pay to take a nap, consequently, I have to go to New York.
by the tree
Thu Jan 21, 2010 3:29 pm UTC
Forum: Mathematics
Topic: Give these Word Problems a Try
Replies: 19
Views: 1979

Re: Give these Word Problems a Try

If you slavishly follow the gaussian elimination algorithm when you row reduce, you'll take a lot longer to get there than someone who's done a few dozen examples by hand. Its one thing to know the algorithm, its another to know how it works so that you can arrive at the destination by a better pat...
by the tree
Thu Jan 21, 2010 11:15 am UTC
Forum: Mathematics
Topic: Help! I wrote this and now have no idea what it means.
Replies: 2
Views: 740

Re: Help! I wrote this and now have no idea what it means.

Can you remember what textbooks you might have been reading at the time? If you locate part 172.B and read that chapter again then it might shed some light on the issue.
by the tree
Thu Jan 21, 2010 11:10 am UTC
Forum: Mathematics
Topic: Give these Word Problems a Try
Replies: 19
Views: 1979

Re: Give these Word Problems a Try

I will go with my 1 word answer of "Maple". Failing that, Gaussian elimination is indeed the way to go. That's not really solving them though - it's asking a computer to solve them for you. It's no problem if I program Gaussian myself, no? :wink: The issue is whether you understand the al...
by the tree
Wed Jan 13, 2010 3:21 pm UTC
Forum: Mathematics
Topic: Mathematics and intellect
Replies: 85
Views: 9618

Re: Mathematics and intellect

Mathsy smart might just be a rarer type of smart than booky smart, making it stand out more.
by the tree
Tue Jan 12, 2010 1:17 am UTC
Forum: Mathematics
Topic: Bicentric quadrilaterals.
Replies: 8
Views: 1203

Bicentric quadrilaterals.

This was a question that occurred to me whilst idly doodling. Given two circles, one contained in the other - what conditions are needed for there to exist a quadrilateral that is tangential to the inner one and cyclic to the outer one? If the two circles are concentric then it appears to relate to ...
by the tree
Sun Jan 10, 2010 12:20 pm UTC
Forum: General
Topic: Just so we're clear...
Replies: 191
Views: 21202

Re: Just so we're clear...

If I may clarify my original position, I'd just like to say that I feel xkcd feeds off of the "emperor's new clothes" phenomenon. The comic is indirectly advertised as being a smart-person's comic (Warning: this comic occasionally contains strong language (which may be unsuitable for chil...
by the tree
Fri Jan 08, 2010 4:50 pm UTC
Forum: Science
Topic: Bladeless fans?
Replies: 18
Views: 1662

Bladeless fans?

Okay so I was just linked to the Dyson Air Multiplier which apparently isn't on the market yet but omigod it looks gorgeous. Now what I don't completely get is how the air is drawn in in the first place, what it looks like is that a regular fan (on it's side) is concealed within the base to draw air...

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