## Search found 18 matches

Sun Apr 01, 2012 6:58 pm UTC
Forum: Mathematics
Topic: Function converges to square root, but why?
Replies: 7
Views: 3832

### Re: Function converges to square root, but why?

The usual trick with recursive series like this is to just substitute the same variable x or something for all instances of f(n-1) etc. so in this case you get: x = \frac{a}{x} + \frac{b}{x} and solving for x gives you x=sqrt(a+b) So if the series does indeed converge that (+-) is what it is...
Tue Nov 01, 2011 12:33 pm UTC
Forum: Mathematics
Topic: Self-referential probability questions
Replies: 16
Views: 4405

### Re: Statistics problem

None of the questions are correct, so 0%. 0% isn't an option so it's true. Building on that: 0 percent is indded only correct because it is not one of the possible answers. So including 0% in place of the 60% answer would actually make this question impossible to answer even if you assumed that thi...
Sun Oct 16, 2011 10:17 am UTC
Forum: Science
Topic: Well, this could change things (neutrinos)
Replies: 289
Views: 44941

### Re: Well, this could change things (neutrinos)

New paper out with an explanation for an early arrival time of about 64 ns. http://arxiv.org/abs/1110.2685 The Michelson-Morley experiment shows that the experimental outcome of an interference experiment does not depend on the constant velocity of the setup with respect to an inertial frame of refe...
Thu Aug 25, 2011 10:15 pm UTC
Topic: 0723: "Seismic Waves"
Replies: 94
Views: 27145

### Re: 0723: "Seismic Waves"

Somebody made a video inspired by this comic showing a heatmap of tweets mentioning earthquakes that also shows an approximation of the seismic waves spreading over time

Sat Jul 30, 2011 3:40 pm UTC
Forum: General
Topic: comparing apples, oranges on google ngram
Replies: 10
Views: 2374

### comparing apples, oranges on google ngram

When I compared the frequency of the words "apple" and "orange" in the english literature over the last 200+ years on google ngram I got this result: http://ngrams.googlelabs.com/chart?content=apple%2Corange&corpus=0&smoothing=3&year_start=1800&year_end=2008 http:...
Wed Jan 26, 2011 7:47 pm UTC
Forum: Mathematics
Topic: Interesting Integral
Replies: 3
Views: 1062

### Re: Interesting Integral

The bounds I eventually arrived at are [-1,1] which gives probably the most simple form for f(x), \frac {1}{\sqrt{1-x^2 }} . And that is the derivative of arcsin(x) on [0,-1]. I'm just wondering how (or wether) I can prove that the result I get in this case holds for all other possible bounds withou...
Wed Jan 26, 2011 5:55 pm UTC
Forum: Mathematics
Topic: Interesting Integral
Replies: 3
Views: 1062

### Interesting Integral

\int_A^B \frac {\text dx}{\sqrt{(x-A)(B-x) }} I had to evaluate this integral as part of my homework last week using integration by substitution (and some massive hints that were given). There are to reasons I wanted to post this here. The first one is that it always evaluates two \...
Sat Nov 27, 2010 10:44 am UTC
Forum: Science
Topic: Space colonisation and gravity
Replies: 17
Views: 1724

### Re: Space colonisation and gravity

Oh I hadn't realised that the earth was that heavy But, the earth is weightless! Actually I just tested by turning a scale upside-down and it turns out the earth weighs 3 pounds and 5 ounces. Relative to my scale. What? That used to be just about five pounds when I made that same measurement just a...
Sun Oct 03, 2010 10:53 am UTC
Forum: Logic Puzzles
Topic: Rush Hour / Gridlock
Replies: 9
Views: 3153

### Re: Rush Hour / Gridlock

I like the look for your flash app, but I can't do anything. I get the hand cursor if I hover over a block, but can't move anything. Oh I didn't programm this. All programmig and design was done by one Corwin Derkatch back in 2002. I just happened to like this very minimalistic and in my mind elega...
Sat Oct 02, 2010 7:32 pm UTC
Forum: Logic Puzzles
Topic: Rush Hour / Gridlock
Replies: 9
Views: 3153

### Rush Hour / Gridlock

http://www.corwin.ca/gridlock/ This is one of many implementations of the board game Rush Hour http://en.wikipedia.org/wiki/Rush_Hour_(board_game) . The Goal in each level is to get the blue block through the hole on the right side of the board by pushing it and the other blocks around. The blocks c...
Wed Sep 01, 2010 10:42 pm UTC
Forum: Science
Topic: Peaceful, but Mad, Uses of Nuclear Weapons
Replies: 76
Views: 7753

### Re: Peaceful, but Mad, Uses of Nuclear Weapons

One peaceful use of nucleart weapons I once read about would be to detonate a hydrogen bomb and to then harvest the energy from the blast somehow finally giving us FUSION POWER (!!!) But I have no idea how the energy from such a blast could actually be converted to elecricity. Windmills?
Sat Aug 07, 2010 12:57 pm UTC
Forum: Mathematics
Topic: Tiling a rectangle: Another surprisingly tricky problem
Replies: 45
Views: 6931

### Re: Tiling a rectangle: Another surprisingly tricky problem

EDIT: I misread the problem because I somehow thought "whole number"="even number" so I solved an entirely different (and apparently much easier) problem. Call any 1*1 rectangle a unit square. Then any improper rectangle will cover an uneven number of unit squares whereas any pro...
Thu Jun 17, 2010 9:13 pm UTC
Forum: General
Topic: Fifa World Cup 2010
Replies: 600
Views: 51726

### Re: Fifa World Cup 2010

What a crazy game. Some great defending by the Swiss, could have had a second too. Spain will probably now start with Villa and Torres upfront and dominate though. That wasn't great defending that was a disgusting bunker. It was pretty good bunker but spain still should have won it. Switzerland fie...
Mon Jun 07, 2010 3:04 pm UTC
Forum: Science
Topic: Bonding/Combining Ba, C, O and N
Replies: 14
Views: 4785

### Re: Bonding/Combining Ba, C, O and N

Whatever the final result is going to be I predict that it is going to be a health hazard and I also predict that it is going to be delicious
Tue Jul 14, 2009 6:47 am UTC
Forum: News & Articles
Topic: 400-bln-euro plan to pump African solar power to Europe
Replies: 64
Views: 4669

### Re: 400-bln-euro plan to pump African solar power to Europe

[...] You still don't produce enery at night [...] For solar cells this would be true. With solar thermal power plants however you can store some of the heat you generate in the daytime and use it during the night to continue producing elecricity. IIRC molten salt is especially efficient for this p...
Wed Jul 01, 2009 8:34 pm UTC
Forum: Science
Topic: Weather conditions an a tidally-locked planet.
Replies: 13
Views: 4955

### Re: Weather conditions an a tidally-locked planet.

But with the surface heating at the hot side, warm air would rise. This would cause the cooler air from the sunset and dark areas to move along the surface, likely bringing moisture with it. The uplifting air at the hot side would cool as it rose, likely leading to precipitation. And still over tim...
Tue Jun 30, 2009 10:37 pm UTC
Forum: Science
Topic: Weather conditions an a tidally-locked planet.
Replies: 13
Views: 4955

### Re: Weather conditions an a tidally-locked planet.

I don't think a tidally-locked Earth sounds like a good plan in any case. Maybe, but I like the whole "everlasting sunset" thing. Although I could probably have that in the polar regions of a rotating planet with a non tilted axis so lets try that first. I think the observed surface tempe...
Tue Jun 30, 2009 8:55 pm UTC
Forum: Science
Topic: Weather conditions an a tidally-locked planet.
Replies: 13
Views: 4955

### Re: Weather conditions an a tidally-locked planet.

Well I think the biggest effect would be that over time all the water on the brighter side would evaporate and snow down on the dark side. There it would just lie around never coming back (sublimation should be negligible). So the brighter side would be extremely dry and hot and the darker side woul...