
The back end of all those products is the Wolfram Engine which is now available free for developers. You may have also used the Wolfram Alpha which claims to be a computational knowledge engine and can also be used to quickly plot some functions.

You can try it immediately on the web in the Wolfram Language Sandbox or register for a basic account at the Wolfram cloud for free. The Wolfram language is a powerful language for interactive computing often times with Mathematica as the front end. The Wolfram Research company has also developed a computer programming language called the Wolfram language besides Mathematica.

It encompasses computer algebra, symbolic and numerical computation, visualization, and statistics capabilities. Mathematica is a very powerful scientific computing program which has been used in many scientific and engineering fields.
