# math

## \$4.23 a day: On the timing of a Black Friday iPad 2 purchase

Apple released the first iPad, the 16GB Wi-Fi-only model for \$499, on April 4, 2010. The \$499 iPad 2 came out 342 days later, on March 11, 2011.

Another way to look at it is that you paid \$1.46 a day for the original iPad before it was obsolete.

We lack the proper sample size for true statistical accuracy, but based on the number of days into a new year Apple released its first two iPads, we can take the average of April 4 (92 days in) and March 11 (69 days in), and guess that the iPad 3 will arrive 81 days into 2012. That would be March 22. That would also mean a 377-day life cycle for the iPad 2.

If you agree to play along with that projection, then the \$499 iPad 2 comes out to costing \$1.33 a day before obsolescence. That's a relative bargain compared with the first iPad.

But what does that mean for the value of an iPad 2 purchased this holiday buying season?

Let's take Black Friday--November 25. There are 118 days between November 25 and our March 22, 2012 guess for the debut of an iPad 3. That translates to \$4.23 a day, or more than three times the daily cost of an original iPad during its life cycle as a new product. For an iPad 2 purchased (or opened) on December 25, that's only 88 days until it's out of date, or \$5.67 a day.… Read more

## Are math skills genetic?

For those who can count very well, there is something vaguely infuriating about doing business with (or even living with) people who can't count past three.

Math, to some, seems so simple, so obvious, that looking at those who struggle with it turns the mathophile into a cruel beast.

Yet new research from Johns Hopkins University suggests that one's abilities at math might entirely be handed down by one's forefathers.

Time Magazine assisted in directing me to this research, which was published in a wonderful magazine called Developmental Science (Sample article: "Preschoolers joke with jokers, but … Read more

## Formulas Lite, an invaluable math and science study guide

Formulas Lite is a collection of important information and tools to help students get through some of the tougher subjects in school.

The meat of the Formulas Lite app is in the Subjects tab, where you'll find a huge database of must-know formulas for mathematics, physics, and chemistry. Within each of these top-level subjects, formulas are further organized by topic. For instance, under mathematics you'll see formulas organized in branches from algebra to statistics. Under physics, you'll see formulas organized in branches from relativity to torque. Within the chemistry section, you'll also find a functional periodic … Read more

## RealCalc works just like the real thing

RealCalc gives your Android mobile device all the mathematical prowess of a traditional, physical scientific calculator. When you first use the app, you'll notice that it looks just like the real thing. The button layout and functions feel familiar, and the act of punching out calculations just seems natural. The bottom half of the screen is dedicated to number keys and common arithmetic operations (multiplication, addition, and so on), while the top half of the screen is dedicated to more complex operations like logarithms, radicals, roots, and trigonometric values. And similar to the scientific calculators we all know and … Read more

Progress in upgrading math's tools has been uneven: blackboards have become whiteboards, but calculators and software have come up short in trying to replicate the speed and simplicity of pencil and paper. Math-o-mir is the result of the surprisingly difficult effort to develop a software-based equation editor to meet that need. It's a free tool with one goal, to make writing and editing mathematical equations as easy and natural as scribbling on a pad. It's not a math engine, design tool, or image editor, though it uses some of the same concepts, such as freehand drawing and … Read more

## Happy Tau Day, everybody!

There's a celebration for everything these days--National Yo-Yo Day, Ice Cream Day, even Corduroy Day. March 14 was Pi Day--3.14... get it? On Pi Day, which celebrates the number that represents the ratio of circumference to diameter of a circle, enthusiasts had pie-eating contests and played educational games.

Guess what today is! It's Tau Day. Tau represents the circumference of a circle divided by the radius, which is approximately 6.28. Today is June 28... get it?

Apparently, people have been celebrating this day for 10 years. On Tau Day last year, theoretical physicist Michael Hartl launched the Tau Manifesto, which explained why pi is confusing and instead should be replaced with tau.

One of his reasons: Since tau is the ratio of circumference to radius of a circle, circles are more naturally defined by their radius than diameter. (Are you still following this?)… Read more

## Freebie Tuesday: Music, e-books, apps, and more!

Yesterday's batch of free iPhone games got me in the mood for more free stuff. I mean, even cheap deals cost money, right? Sometimes you just gotta give the credit card a rest.

With that in mind, I've rounded up a handful of freebies for today. Nothing earth-shattering, but some worthwhile stuff to satisfy your daily-deal sweet tooth.

First up, Amazon is offering a free \$2 credit for use at its MP3 store. Just click that link and enter code CLOUDMP3. Presto: you've got two bucks to blow on the songs or album of your choice. (If … Read more

## EmWave2: Portable stress relief for harried geeks

It can be hard to get a techie to relax. We are often found toiling away at Internet start-ups, programming under pressure, or blasting away at Call of Duty as enemies swarm across the lines.

The new emWave2 stress management system from HeartMath features several components that geeks love: a gadget, a computer program, and lots of cool graphs. It also has 20 years worth of stress research behind its development, but the glowing lights are what first catch your eye.

According to HeartMath, emWave technology is already being used by more than 10,000 health professionals, including 65 Veteran Administration hospitals and clinics for post-traumatic stress disorder treatment. The second-generation emWave2 is designed for personal use and is portable enough to tuck in your pocket. It also adds a computer interface and desktop program that can track your results, and it has several additional applications including a slideshow and a garden game that adds colors and images as you relax.

I got my hands on the emWave2 and took it for a stress-test drive. The \$229 kit includes both an ear and a thumb monitor for your heart rate. I used the thumb monitor. It also includes a line of blue lights that give you visual feedback for controlling your breathing.… Read more

## World's Ultimate Brain tests your intellectual agility

Save for the cheesy name, World's Ultimate Brain is quite a well-put-together puzzle game for Android. It tests your brain's speed and agility across four different categories: Calculation, Memory, Visual Recognition, and Logic. Your simple job is to race the clock and answer as many questions correctly as possible. Once you finish, the app will calculate your score, and submit it to the worldwide leaderboard. If you're extra proud of your intellectual skills, you can even have it post your score to Facebook, Twitter, or (inexplicably) MySpace.

While World's Ultimate Brain is indeed fun, easy to … Read more

## High school math wiz wins Intel Talent Search

Honoring some of the nation's brightest high school seniors for achievements in math and science, Intel yesterday awarded the three highest prizes in its Science Talent Search for three very different types of projects.

The top prize of \$100,000 went to Evan O'Dorney, 17, of Danville, Calif., for a project in which he compared two ways to estimate the square root of an integer, discovering which one was the quickest. Though that may sound abstract to non-math people, the results of O'Dorney's research allowed him to solve other equations that could be used to encrypt … Read more