## Search found 143 matches

- Wed Oct 03, 2012 2:29 am UTC
- Forum: Mathematics
- Topic: Circle theorem question
- Replies:
**7** - Views:
**4697**

### Circle theorem question

In the diagram below, A, B, C, D are four points on a circle. P is a point such taht PA and PC are tangents to the circle. D, B and P lie on a straight line. M is a point on DB such that DCM = ACB. Given that CMD = 105° and BCP = 55°, find BAC. [1] http://i.imgur.com/evpRG.png Stuck on this question...

- Thu Mar 29, 2012 1:40 pm UTC
- Forum: Mathematics
- Topic: Finding the probability of a probability being at least 0.75
- Replies:
**12** - Views:
**2943**

### Re: Finding the probability of a probability being at least

But starting off with "you play against someone named Chris" does not allow this. There's no random process involved. The two persons are arbitrary, not random. Subtle, but important difference. Because you don't know who "Chris" is, your expected strength against "Chris&qu...

- Mon Mar 26, 2012 12:50 pm UTC
- Forum: Mathematics
- Topic: Finding the probability of a probability being at least 0.75
- Replies:
**12** - Views:
**2943**

### Finding the probability of a probability being at least 0.75

*not homework* The probability of you winning a chess match against someone, say "Chris", is "x". How many games do you have to win in a row in order for the probability of "x" being higher than 75% be 0.9? I know this probably isn't the most accurate way of measuring a...

- Mon Mar 19, 2012 2:45 pm UTC
- Forum: Individual XKCD Comic Threads
- Topic: 1002: "Game AIs"
- Replies:
**251** - Views:
**110505**

### Re: 1002: "Game AIs"

So, where should we put shogi on the comic strip? Before or after arimaa (because I guess go is undisputed champion)? Arimaa was specificaly made to be hard for AI. Omar Syed is offering a man-vs-machine challenge, but only until 2020 ... This suggests that it might be as difficult as suspected. I ...

- Wed Mar 14, 2012 12:46 pm UTC
- Forum: Mathematics
- Topic: Quadratic Equations and 13 year old boys...
- Replies:
**14** - Views:
**2565**

### Re: Quadratic Equations and 13 year old boys...

aren't quadratic equations taught at age 13?

- Mon Dec 12, 2011 1:11 pm UTC
- Forum: Mathematics
- Topic: Finding original expression using differences between terms?
- Replies:
**4** - Views:
**1003**

### Re: Finding original expression using differences between te

very interesting. thanks!

- Mon Dec 12, 2011 9:44 am UTC
- Forum: Mathematics
- Topic: Finding original expression using differences between terms?
- Replies:
**4** - Views:
**1003**

### Finding original expression using differences between terms?

Let's say we have the function f(x) = x 2 . If we have enough values of it we can theoretically find the original (x 2 ) by computing its differences. 1 4 9 16 3 5 7 2 2 Questions: 1) How to use the differences computed to find the original, rather than just knowing what the highest power is. 2) If ...

- Mon Jan 17, 2011 10:18 am UTC
- Forum: Coding
- Topic: im building an aquarium
- Replies:
**31** - Views:
**12907**

### Re: im building an aquarium

Do you want to Digg it? If you tweet it I will definitely retweet. It seems so far that you are the first one to build the Aquarium...

- Sat Jan 15, 2011 3:41 am UTC
- Forum: Coding
- Topic: im building an aquarium
- Replies:
**31** - Views:
**12907**

### Re: im building an aquarium

This is so exciting! I can't wait for the final product! Keep going and never give up!

EDIT: Minor spelling error

EDIT: Minor spelling error

- Sat Jan 15, 2011 1:45 am UTC
- Forum: Mathematics
- Topic: Determining stable discs in Reversi
- Replies:
**3** - Views:
**1299**

### Re: Determining stable discs in Reversi

Thanks blue and moose, those are great ideas! However, because my AI already looks to the future, there is no need to determine 3, because 3 will soon become apparent to it. I don't understand what you mean by 1 and 2. Also, thrash recursion. We are not finding if ONE disk is stable or not, we are f...

- Fri Jan 14, 2011 1:30 pm UTC
- Forum: Mathematics
- Topic: Determining stable discs in Reversi
- Replies:
**3** - Views:
**1299**

### Determining stable discs in Reversi

How do I determine stable discs in reversi? One obvious way is to play every move possible till the end of the game. If there were any pieces not flipped, that disc is stable. However, there are too many possibilities that it'll take too long. One observation is that corners cannot be flipped. If co...

- Thu Jan 13, 2011 9:17 am UTC
- Forum: Coding
- Topic: The "IT DOESN'T WORK!" thread
- Replies:
**1963** - Views:
**571491**

### Re: The "IT DOESN'T WORK!" thread

yes. I will try and then edit this post

missilen: values from 0 to 43(when I stopped the program) are all 1

missile: 0 to 43 all contain different values. however, only 1 missile is shown on the screen.

missilen: values from 0 to 43(when I stopped the program) are all 1

missile: 0 to 43 all contain different values. however, only 1 missile is shown on the screen.

- Sat Jan 08, 2011 5:51 pm UTC
- Forum: Coding
- Topic: The "IT DOESN'T WORK!" thread
- Replies:
**1963** - Views:
**571491**

### Re: The "IT DOESN'T WORK!" thread

Um sorry, that really doesn't work. And I really need help.

- Sat Jan 08, 2011 11:55 am UTC
- Forum: Coding
- Topic: The "IT DOESN'T WORK!" thread
- Replies:
**1963** - Views:
**571491**

### Re: The "IT DOESN'T WORK!" thread

Me: "IT DOESN'T WORK!" You: "What doesn't work?" Me: "THE CODE!" You: "What code?" Me: if (_root.type == 2) { i = 0; n = 0; c = 0; missilen = new Array(); missile = new Array(); this.onEnterFrame = function() { found = 0; while (!found) { if (missilen[c] != 1)...

- Sat Jan 08, 2011 10:03 am UTC
- Forum: Logic Puzzles
- Topic: Yet Another Cipher.
- Replies:
**8** - Views:
**3120**

### Re: Yet Another Cipher.

"helloworld" --> 10 characters 83641218461229490 --> 17 characters "thequickbrownfoxjumpedoverthelazydog" --> 36 characters 798105542002147970710225311122677209830872686206338605468406151358823 --> 69 characters original text --> 3538 characters. nothing to reveal here, other tha...

- Sat Jan 08, 2011 9:22 am UTC
- Forum: Mathematics
- Topic: Encrypted letter to Fermilab
- Replies:
**15** - Views:
**5274**

### Re: Encrypted letter to Fermilab

Darn! N

ow

I wan

t to

send s

ome mind-b

oggling e

ncrypted me

ss

age to so

me random company for them to decode

! Containing nothing!

ow

I wan

t to

send s

ome mind-b

oggling e

ncrypted me

ss

age to so

me random company for them to decode

! Containing nothing!

- Mon Nov 08, 2010 1:12 pm UTC
- Forum: Science
- Topic: Floating space?
- Replies:
**12** - Views:
**1524**

### Re: Floating space?

I once thought about this, I am also interested in the answer...

- Mon Nov 01, 2010 10:54 am UTC
- Forum: Mathematics
- Topic: How many digits of Pi do you know?
- Replies:
**445** - Views:
**108306**

### Re: How many digits of Pi do you know?

Some of the properties of pi are pretty interesting, for instance the distribution of the digits of pi in base 10 (ie does any digit appear more often than another). There are still a lot of unproven conjectures about the digits of pi, and knowing the digits gives us that slight edge in proving the...

- Mon Oct 25, 2010 12:02 pm UTC
- Forum: Logic Puzzles
- Topic: Relatively prime
- Replies:
**21** - Views:
**3957**

### Re: Relatively prime

Ah well, why not a follow-up question? How many such pairs are there at least? And what kind of a number has n got to be to attain this value? My answer(not sure if it's right) spoilered here: 14 pairs, and n doesn't really matter... No, thats wrong. Different samples yield different numbers of...

- Mon Oct 25, 2010 10:49 am UTC
- Forum: Mathematics
- Topic: Linear regression of an exponential equation
- Replies:
**2** - Views:
**509**

### Re: Linear regression of an exponential equation

y = f*p^x

log

ln y/ln p = ln f/ln p + x

log

_{p}(y) = log_{p}(f) + xln y/ln p = ln f/ln p + x

- Sun Oct 24, 2010 11:49 am UTC
- Forum: Mathematics
- Topic: Calculus Homework question that I'm stuck on
- Replies:
**10** - Views:
**1228**

### Re: Calculus Homework question that I'm stuck on

What is the practical meaning of L(25)= 235? What are the units of L' (23)? What is the practical meaning of L' (20)= 25? Estimate L(26) Okay, so there are your questions, here it is again, 1) What is the practical meaning of L(25)= 235 2) What are the units of L' (23) 3) What is the practical mean...

- Sat Oct 23, 2010 2:30 pm UTC
- Forum: School
- Topic: Your Favorite Teacher(s)
- Replies:
**29** - Views:
**4208**

### Re: Your Favorite Teacher(s)

I have to say, I love all my teachers this year. They are ALL GREAT! all of them would go into deep detail and explain everything in depth.

- Sat Oct 23, 2010 2:08 pm UTC
- Forum: Forum Games
- Topic: Count up in Hex
- Replies:
**1472** - Views:
**200212**

- Sat Oct 23, 2010 1:45 pm UTC
- Forum: News & Articles
- Topic: Wikileaks releases 400 000 Iraq war documents
- Replies:
**6** - Views:
**1722**

### Re: Wikileaks releases 400 000 Iraq war documents

:O Oh me yarm! I... I don't know what to say!

- Sat Oct 23, 2010 1:37 pm UTC
- Forum: Forum Games
- Topic: Maximize the post:views ratio! (if you look, you must post)
- Replies:
**36982** - Views:
**2489356**

- Sat Oct 23, 2010 1:37 pm UTC
- Forum: Forum Games
- Topic: Maximize the post:views ratio! (if you look, you must post)
- Replies:
**36982** - Views:
**2489356**

- Sat Oct 23, 2010 1:37 pm UTC
- Forum: Forum Games
- Topic: Maximize the post:views ratio! (if you look, you must post)
- Replies:
**36982** - Views:
**2489356**

### Re: Maximize the post:views ratio! (if you look, you must p

asdfadsfadsf! AHHHHAHHHHHHHH!!

- Sat Oct 23, 2010 12:12 pm UTC
- Forum: Science
- Topic: What science tweeters do you follow?
- Replies:
**9** - Views:
**1834**

### Re: What science tweeters do you follow?

Math don't count! BUT feel free to change it to: What tweeters do you follow?

- Sat Oct 23, 2010 9:06 am UTC
- Forum: Mathematics
- Topic: Help a kid with Calculus!
- Replies:
**55** - Views:
**4654**

### Re: Help a kid with Calculus!

Ok, I'm prepared.

I'm ready for a range of questions starting from easy to overkill. Then maybe you would know what I have yet to search.

I'm ready for a range of questions starting from easy to overkill. Then maybe you would know what I have yet to search.

- Sat Oct 23, 2010 5:00 am UTC
- Forum: Mathematics
- Topic: Help a kid with Calculus!
- Replies:
**55** - Views:
**4654**

### Re: Calculus (more specifically Integral Calculus)

Here I go again! :D 1. d/dx(x*y 2 + tan(32/x)) = (hint: d/dx(tan(x)) = sec 2 (x) = 1/cos 2 (x) ) d/dx(x*y 2 )+d/dx(tan(32/x)) y 2 +2xy(dy/dx)+sec 2 (32/x) * d/dx(32/x) y 2 +2xy(dy/dx)+sec 2 (32/x) * -32/x^2 y 2 +2xy(dy/dx)-(32sec 2 (32/x))/x^2 I think i got it right! :D Edit: no, wolfram alpha didn'...

- Fri Oct 22, 2010 2:12 pm UTC
- Forum: Your art and links
- Topic: Font discussion
- Replies:
**11** - Views:
**4913**

### Re: Font discussion

Buy a penmanship book, and DON'T PRESS DOWN. It really works!

- Fri Oct 22, 2010 1:21 pm UTC
- Forum: Mathematics
- Topic: Help a kid with Calculus!
- Replies:
**55** - Views:
**4654**

### Re: Calculus (more specifically Integral Calculus)

1. d/dx(x*y 2 + tan(32/x)) = (hint: d/dx(tan(x)) = sec 2 (x) = 1/cos 2 (x) ) d/dx(xy 2 ) + d/dx(tan(32/x)) 2y*dy/dx + d/dx(tan(32 x -1 )) 2y*dy/dx + sec 2 (32 x -1 )(-32 x -2 ) 2y*dy/dx + (-32 x -2 )/cos 2 (32 x -1 ) 2y*dy/dx + (-32/x 2 )/cos 2 (32/x) 2y*dy/dx - 32/(cos 2 (32/x)*x 2 ) Wolfram Alpha...

- Fri Oct 22, 2010 12:37 pm UTC
- Forum: Mathematics
- Topic: Help a kid with Calculus!
- Replies:
**55** - Views:
**4654**

### Re: Calculus (more specifically Integral Calculus)

do I assume it's equal to 0?

EDIT: oh well I'll just go and try it out

EDIT: oh well I'll just go and try it out

- Fri Oct 22, 2010 12:05 pm UTC
- Forum: Mathematics
- Topic: Help a kid with Calculus!
- Replies:
**55** - Views:
**4654**

### Re: Calculus (more specifically Integral Calculus)

? I got equations with x and y in them when I learnt them from the net. So what am I supposed to do?

- Fri Oct 22, 2010 11:15 am UTC
- Forum: Mathematics
- Topic: Help a kid with Calculus!
- Replies:
**55** - Views:
**4654**

### Re: Calculus (more specifically Integral Calculus)

Try to answer the following: 1. d/dx(sin 2 (x)) = d/dx((sin(x)) 2 ) = (cos(x)) 2 not even sure about the sin-->cos and cos-->sin thing, very unsure, just need more practice problems ack! EDIT: got this wrong, should be 2sin(x)cos(x) from the outside in. 2. d/dx(ln(x+3)) = 1/(x+3)*1 = 1/(x+3) Note: ...

### Re: Minecraft

about 9 to 13. 9 if you want small trees, 13 if you want to go through all that trouble whacking everything down (not recommended)

- Fri Oct 22, 2010 10:21 am UTC
- Forum: Mathematics
- Topic: Help a kid with Calculus!
- Replies:
**55** - Views:
**4654**

### Re: Calculus (more specifically Integral Calculus)

but how would i know that the inside is another function? if i can't expand it out?

- Fri Oct 22, 2010 9:28 am UTC
- Forum: Forum Games
- Topic: Count up in Hex
- Replies:
**1472** - Views:
**200212**

- Fri Oct 22, 2010 8:38 am UTC
- Forum: Mathematics
- Topic: Time. 6:30 or 6.30?
- Replies:
**25** - Views:
**3551**

### Re: Time. 6:30 or 6.30?

time is base 60, so 1.30 is 1.5 in base 10

EDIT: well then we have a problem with the hours, we still need a metric system.

EDIT: well then we have a problem with the hours, we still need a metric system.

- Fri Oct 22, 2010 8:09 am UTC
- Forum: Mathematics
- Topic: Time. 6:30 or 6.30?
- Replies:
**25** - Views:
**3551**

### Re: Time. 6:30 or 6.30?

hey, they tried to do that to make everything match up with the metric system, and i totally vote using base 10 for time. I mean ALL of time.