$ProcessorType (Built-in Mathematica Symbol)

$ProcessorType is a string giving the architecture of the processor on which Mathematica is being run.

$SystemCharacterEncoding (Built-in Mathematica Symbol)

$SystemCharacterEncoding gives the default raw character encoding for the computer system on which Mathematica is being run.

$System (Built-in Mathematica Symbol)

$System is a string describing the type of computer system on which Mathematica is being run.

$UserDocumentsDirectory (Built-in Mathematica Symbol)

$UserDocumentsDirectory gives your default "documents" directory.

$Version (Built-in Mathematica Symbol)

$Version is a string that gives the version of the Mathematica kernel you are running.

Adding, Removing, and Modifying List ... (Mathematica Tutorial)

Functions for manipulating elements in explicit lists. This gives a list with x prepended. This inserts x so that it becomes element number 2.

Calculus (Mathematica Overview)

Differentiation Total Derivatives Derivatives of Unknown Functions

Core Language (Mathematica Overview)

"How to" Topics Building Up Calculations Lists

Differences between Computer Systems (Mathematica Tutorial)

There are many detailed differences between different kinds of computer systems. But one of the important features of Mathematica is that it allows you to work and create ...

Efficient Representation of Many ... (Mathematica Tutorial)

Primitives which can take multiple elements. Some primitives have multi-element forms that can be processed and rendered more quickly by the Mathematica front end than the ...