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

You are not logged in.

## #1 Re: Maths Is Fun - Suggestions and Comments » Implicit Equation Grapher » 2009-12-18 10:41:29

(sin(x^2)+sin(x^2*y^2))^(1/2)+x/y=(cos(x^2*y^2)+cos(y^2))^(1/2)+y/x

1 = (y*x)^12*sin(x^2+y^2)

Try to find the partial implicit derivatives of the first one. If you can't be bothered, use http://www.wolframalpha.com/. They're insane. Good luck finding them without making a mistake.

## #2 Re: Dark Discussions at Cafe Infinity » Talking to people about scores » 2009-12-18 10:15:21

I usually just respond with stuff like:
-"Oh, okay. Are you not satisfied with that?"
--"No, I had expected to do a lot better"
-"Okay, well... Anything in you found hard in particular?"
--"Yeah, I had trouble with the..."
-"That drags.. well, we can run trough some examples if you want."
blablabla

Normally I keep asking questions, to avoid the "how about you?", but then again I don't really feel people get upset when I tell them I got a higher score.

## #3 Re: Help Me ! » Im Pround of my Brother » 2009-12-18 10:10:05

Well, congratulations to him.

## #4 Re: Maths Is Fun - Suggestions and Comments » Fundamental Theorem of Algebra » 2009-12-17 10:54:35

Why not keep it simple and clear?

You might aswell do it right.

Also, thought about proving the following, or is it out of your scope?

## #5 Re: Help Me ! » Improper Integrals » 2009-11-02 01:36:19

Thank you so much I had a feeling I was doing it wrong, glad you took the time to explain it. Thank you

## #6 Help Me ! » Improper Integrals » 2009-11-02 00:35:20

Patrick
Replies: 2

I have the following improper integral:

And I'm getting the following:

Because as far as I can argue, I get:
and

Am I right, or have I made a mistake?

## #7 Re: Help Me ! » Geometric series » 2009-10-14 03:14:47

I found out, that 0^0 = 1, so my problems are solved

edit:(in this context)

## #8 Re: Help Me ! » Geometric series » 2009-10-13 06:16:23

Thanks for taking the time to help, but I'm not sure what the last part means (after the but), and why you write sqrt(x) is less than a half?

## #9 Help Me ! » Geometric series » 2009-10-12 22:49:15

Patrick
Replies: 3

I'm looking at the series:

I have to find in what interval I it's convergent. I'm having trouble deciding if it's I=]0,1[, or I=[0,1[. If I write it 'out', I get:

Here's the problem. I say that it's a geometric series with a=1 and r=sqrt(x). We have that |r|<1 if it has to be convergent. This means:

Combined with x greater than or equal to 0, I get:

The thing I don't get though, is that if x is 0 (as allowed in my I) I get:

Which starts with an 0^0. Which leads me to I=]0,1[. Which is right? Or what am I missing? A definitionissue perhaps?

Very nice

## #11 Re: Maths Is Fun - Suggestions and Comments » LaTeX problem » 2008-09-05 06:46:37

mathsyperson - the problem is that all the LaTeX is generated and rendered as a picture-file (don't remember if it's png, or?)... Storage isn't infinite, and 3 different backgrounds means 3 times the space needed.

Try to save it:

(I found out it was gif)

## #12 Re: Maths Is Fun - Suggestions and Comments » Open Sentences » 2008-09-05 06:43:09

Very basic, but no subject is too basic or short to be included on a site like this.

P.s.: Everything looks like it used to be Hello everyone

Why?

## #14 Re: Dark Discussions at Cafe Infinity » Wikipedia 2 Million Articles » 2007-10-05 09:05:22

shocamefromebay wrote:

i realy wonder about what really makes an article legitimte (excuse my spelling) for wikipedia
i mean
there are those ppl who post biographies of themselvs
which is kinda not awesome
but what really makes an artcle legit???
there was once an artice that i found that was of an organiztion
which was kind of lgit
but it was also very unorganized
but then it got deleted quickly

so back to my first question

there are loooots of rules/guidelines at wikipedia, on how to write articles.. start here http://en.wikipedia.org/wiki/Wikipedia:Contributing_to_Wikipedia

## #15 Re: This is Cool » Domestos Kills Germs! » 2007-10-05 08:57:49

Devantè wrote:

This is why society is full of sickness. We're too clean. I'd like to see a few more tests on that matter.

This is absolutely true. I've read about his, though I have no links or evidence. It was about as study where one group of children were allowed to get dirty when they were playing outside, and another group of children weren't. Result: the dirty children were much more resistant to a variety of diseases when they were in their teens.

Also, I think that humanity has to think about their use of medicine. We're basically allowing more and more 'bad' DNA, by keeping people alive who would have died if it was up to nature. Obviously, I can't make a law, which says that sick people can't be treated, no one would give me support.

## #16 Re: This is Cool » Quantum Computing now on a Chip » 2007-10-05 08:50:37

Identity wrote:

If I lay down and keep saying "WHY!" to myself, I would slowly turn mad.

I'm not sure you would actually TURN mad, but people would certainly believe you were...

## #17 Re: This is Cool » Quantum Computing now on a Chip » 2007-10-03 07:29:22

Anthony.R.Brown wrote:

Quote:" Well you have to ask a better question if you want an answer, why what? "

A.R.B

Exactly that´s the Question! " WHY " not what?

Saying "Why?" makes just as much sense as saying "What?",..., "Who?" or "Where?" all by itself... I guess you're talking about the question "Why do we exist?" or perhaps "Why is the Universe?" etcetera?

## #18 Re: This is Cool » Quantum Computing now on a Chip » 2007-10-03 03:32:06

Anthony.R.Brown wrote:

It's a Shame it still wont be able to answer the Ultimate Question! " WHY " ?

A.R.B

Well you have to ask a better question if you want an answer, why what?

## #19 Re: Maths Is Fun - Suggestions and Comments » Subtraction » 2007-08-10 00:38:30

In school I learned the method shown on the site, but I've always used the method explained by luca..

## #20 Re: This is Cool » This is not cool, but sad! » 2007-08-09 11:09:13

Can't believe I didn't check the source ... http://en.wikipedia.org/wiki/Yoknapatawpha_County

## #21 Re: Dark Discussions at Cafe Infinity » The Atom Smasher » 2007-08-09 07:46:48

Identity wrote:

It is just a theory.

AHEM... Someone needs to brush up their terminology. In physics, and mathematics for that matter, a theory is not a speculation or an idea based on someone's opinion. However, if what you meant was, that Hawking Radiation is more like a conjecture or even just a speculation(I mean something generally believed to be true), then sure; it might be a concern. I'm not familiar with Hawking Radiation, though, so I won't be able to tell if it's a theory or not. Just noticed your little statement about something being 'just a theory'

## #22 Re: Maths Is Fun - Suggestions and Comments » Theoryforums.com WANT!! WANT!!! » 2007-08-09 07:31:31

I'm not sure I follow? What's 'stupid' about theories?

## #23 Maths Is Fun - Suggestions and Comments » Code formatting » 2007-08-09 07:30:31

Patrick
Replies: 1

Since we now have a Coder's Corner, I think perhaps an update of the good ol'  ['code]['/code] function could be nice.

``````#include <stdio.h>

int main(){
if(!MathIsFun) printf("Cry!");
return 0;
}``````

Instead of the above, you would get something like:

#include <stdio.h>

int main(){
if(!MathIsFun) printf("Cry!");
return 0;
}

You would probably need to do something like. Since I only know PHP and C, I'm not sure about all the other languages, but I guess you could just make a huge list of all the names of functions in C, PHP, C++, JAVA, ..., and then make all functions one colour. So it could be used for all/most programming languages. Is this possible to implement?

## #24 This is Cool » This is not cool, but sad! » 2007-08-09 07:16:10

Patrick
Replies: 5

http://www.snopes.com/lost/fraction.htm

Read it. I really hope that the law got reversed or something. The reasoning that teaching children illogical things as "irrational numbers" or "imaginary numbers" is just embarrassing for the people who voted for the person. Clearly the 'daily' use of the words irrational and imaginary does not apply here. Sad...

## #25 Re: Maths Teaching Resources » Downloadable Graphics Calculator » 2007-07-17 00:22:02

love this part of the site:
http://www.graphcalc.com/y2k.shtml