Expressions
===========

1. Evaluate manually the following expressions. Then type them in a
   Python shell and check the result.

   a) Division
   
   .. code:: python
	     
      15/3
      15//3
      17/3
      17//3
      17%3
      -17//3
      -17%3
      17/-3
      -17/-3
   
   b) Priority rules
   
   .. code:: python
	     
      3*4+2
      (3*4)+2
      3*(4+2)
      7+2**3
      7+(2**3)
      (7+2)**3
      2**2**3
      2**(2**3)
      (2**2)**3

   c) Boolean expressions
   
   .. code:: python
	     
      2 > 4 or 2 > 1
      2 > 4 and 2 > 1
      2 < 4 and not(3 > 5 or 7 < 8)
     
   d) Expressions with strings
   
   .. code:: python
	     
      'How' + ' are ' + 'you ?'
      'Fine '*3
      'I have '+ str(3) + ' sisters.'

2. Write the following mathematical expressions using the Python
   syntax (use the minimum number of parenthesis):

   a) :math:`\frac{x+2y-1}{z}`
   b) :math:`\frac{4x}{2y+3z}`
   c) :math:`\frac{5xy}{2z}`
   d) :math:`\frac{x}{4yz}`
   e) :math:`\frac{x^5}{3} + \frac{(2x-1)^3}{6} + \frac{x}{12} + 1`
   f) :math:`\frac{y^3 \tan x}{cos(y^2)-3}`
   g) :math:`\frac{|8x-4y|}{\sqrt{x^2+cos(y)+4}}`

   You can find the solution in file :download:`expressions.py<expressions.py>`