# Archive for May, 2009

## Inspiring speech by Steve Jobs

Posted by Ed on May 30, 2009

In 2005 Steve Jobs gave a speech to the Stanford graduates. It is so inspiring that parts of it are quoted now on the internet, here are my favorite parts:

1. “Don’t let the noise of others’ opinions drown out your own inner voice.”
2. “Stay Hungry. Stay Foolish.” (this one is from “The Whole Earth Catalog”)

Watch the speech here.

## Maxima – A free Computer Algebra System

Posted by Ed on May 17, 2009

Computer Algebra Systems (CAS) are programs that allow manipulating equations. That is their specialty lies in the ability to manipulate symbols. For example if I wanted to expand
$(x+y)^3$
the result would be
$(x+y)^3 = x^3 + 3 x^2 y + 3 x y^2 + y^3$
Maxima is such program and the best is that it is freely available.
If you want to determine the integral of
$(\text{sin}(x))^2$
then Maxima tell you
$\int (\text{sin}(x))^2 dx= \frac{x-\frac{\text{sin}\left( 2\,x\right) }{2}}{2}$
There is a very nice 10 minute tutorial on Maxima here.