Wolfram Alpha

This is one of my favorite sites.   I often refer my students to this service.  This site  has both a free and paid services. The free service is adequate for most calculations.  When you enter a function:

• It will give a graph of the function.   For instance lets say you enter xsinx and it will graph the function.  This will give you a graph for just about any function that you enter.  This is a graphing calculator.
• The calculator will give you the domain and range of the function.
  
• This will give you a series representation of the function.
• This will give you an improper integral of most functions if the derivative exists.
  
• This will give you a derivative of most functions if the derivative exists.
• This will find the maxima and minima of the function.
• This will give you and alternate function.

This site is recommended for:

Arithmetic
Pre-algebra
Algebra 1
Algebra 2
Pre-Calculus
Calculus
Linear algebra

Students
Teachers
Professionals