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Re:Why is this a bad thing? by Anonymous Coward · 2007-08-10 19:46 · Score: 0 · on Discouraging Students from Taking Math

x*x = 25 is an example of a quadratic equation. The "solutions" to this equation are the numbers that make the equation true when you plug them in for x. Here the solutions are x=5 and x=-5 since 5*5 = 25 and (-5)*(-5) = 25.

In general, an equation is "quadratic" if it looks like this:
a*x*x + b*x = c
where a, b, and c are fixed numbers (constants). In the previous example, x*x = 25, is the same as 1*x*x + 0*x = 25, which fits the form of a quadratic equation with a = 1, b = 0, and c = 25.

You can find the solutions to any quadratic equation with a method called "completing the square". A good geometric/pictorial explanation of completing the square can be found here:
http://img172.imageshack.us/img172/3415/completesq uarexl1.png
(note that in that image the starting equation is slightly different, but essentially the same if you divide both sides by a and rename the constants)

You can also gain intuition about quadratic equations by graphing them. To graph a quadratic equation, you make it so that the right hand side is no longer a constant, but rather a variable. eg: x*x = 25 -> x*x = y = ? . Then you pick values of x, compute the y that they correspond to, and then plot those (x,y) pairs as points on a graph. The vertical position of the point is the y value, and the horizontal position is the x value. If you do this for a lot of values of x, the shape that emerges is a curve called a parabola.

Another way to think of the solution to a quadratic equation x*x = 25 is the horizontal position of the intersection of the parabola graph of x*x = y, and the horizontal line at height y = 25. This is because the parabola is all points (x,y) where x*x = y, and the line is all points where y = 25, so the places where the line intersects the parabola are the points (x,y) where y = 25 and x*x = 25.

The corrected temperature plot by Anonymous Coward · 2007-08-10 06:37 · Score: 1, Informative · on Blogger Finds Bug in NASA Global Warming Study?

All you guys, do yourself a favour and plot NASA's corrected data in your favourite plotting program

Here's a plot courtesy of gnuplot.

(Posted anonymously because people are completely irrational about global warming.)

Re:Ubuntu drive partition by fimbulvetr · 2007-08-05 01:29 · Score: 1 · on Tales of Conversion - Using Ubuntu at Work

Well it's pretty obvious - either that or you don't know how to read.

Check it out:

http://www.psychocats.net/ubuntu/installingdappere dgy

http://img230.imageshack.us/img230/2340/w2u260tf.p ng

First option:

Resize IDE MASTER Partition #1 and used freed space

Here's another:

http://www.ubufied.com/2006/11/01/ubuntu-610-insta llation-with-screenshots/

Says the same thing.

So obviously, you are making this up. Even the windows based installer offers you the option to resize and use freed space.

Re:Uh... "Forensic Analysis" my foot by ben+there... · 2007-08-03 08:44 · Score: 1 · on Forensic Analysis Reveals Al-Qaeda's Image Doctoring

There has been some real (peer reviewed) research on detecting digital forgeries by Dr. Hany Farid and his lab at Dartmouth:
http://www.cs.dartmouth.edu/~farid/research/tamper ing.html Oh, you mean the dude he thanks in his presentation? (warning: 32 MB PDF. I'll save you the 2 min wait. Here's a screenshot.)