[ch-01] Solution for the first problem

@rmascarenhas @andrielfn @fabioyamate please review.

This is the compiled version for the `tex` file.

![screen shot 2014-07-15 at 8 54 50 pm](https://cloud.githubusercontent.com/assets/611891/3592985/762c41cc-0c7b-11e4-9bf7-2c878ab775ee.png)