sympy/sympy — pull request #1165 by ashfall (2012-03-22 15:52:53+00:00)
Title: Tweaked examples/beginner/ to fix some errors, improve readability and add descriptions

Made the following changes:

differentiation.py : Modified the examples to make it more illustrative, added descriptions.
expansion.py : Added descriptions.
limits_examples.py : Adjusted spacing in the import statement to follow the code conventions.
precision.py : Added descriptions.
substitution.py : Fixed error in importing "sympy.Float" module.