I would like to suggest a brain teaser: The barber is a man in town who shaves all those, and only those, men in town who do not shave themselves. Does the barber shave himself? According to the statement…

## The quiz of the day

As I've started reading more about pure and discrete mathematics I've encountered a very interesting problem and thus I thought it would be just an interesting quiz for this weekend. The quiz of the day What is the number that…

## Differential equations: estimating the time of death

For those who still haven't found the usefulness/beauty of math (and in particular calculus) I propose a small real-life application inspired by a CSI episode: estimating the time of death. The problem Let's suppose that you are a crime investigator…

## Derivative applications in real life

The derivative has probably unlimited applications in physics, biology, economics and generally in real life. But let's see how we can use it to solve simple problems like optimizing the usage of a metal sheet when we want to build…

## Equation of the tangent to the curve at a point

Calculus is one of those branches of math that I must say I love it. It help us to find solutions to problems where the other branches fail. The following is just an example where calculus allows us to find…

## Creating multi-volume tar.bz2 archives

One thing I love about Linux is its flexibility. Linux is like a Lego: many pieces that you can stick together just to get something different that no one thought about before. The following is just an example of its…

## Installing WordPress on IIS 6

I'm working lately on plug-ins development for my WordPress blog (mynixworld.info). There are thousands plug-ins available out there but some are either limited, not well written, obsolete or buggy. I have written several plug-ins that I want to make available…

## Recharging alkaline batteries

"Most alkaline batteries available are disposable, designed to be used until exhausted, then discarded." (source Wikipedia). That's probably true. The most of us just throw these batteries to the disposal bin because we believe they are not rechargeable. We believe…

## Math can be sweet

I come to you with a simple problem which hopefully any of you can solve it. Although the final solution is what certifies that the problem has been solved correctly I am more interested to see the approach that each…

## 5W solar battery charger for 5 bucks

A while ago I bought 40pcs poly-crystaline solar cells (5 x 2 cm2) with the hope that I will find some spare time to build a small 5W solar battery charger. Each cell provides an average of 0.28A @ 0.5V…