expr[[i]] or Part[expr, i] gives the i\[Null]^th part of expr. expr[[-i]] counts from the end. expr[[i, j, ...]] or Part[expr, i, j, ...] is equivalent to expr[[i]][[j]] .... ...

Information[symbol] prints information about a symbol.

In just one Mathematica command, you can easily specify a calculation that is far too complicated for any computer to do. For example, you could ask for ...

Module[{x, y, ...}, expr] specifies that occurrences of the symbols x, y, ... in expr should be treated as local. Module[{x = x_0, ...}, expr] defines initial values for x, ...

Options[symbol] gives the list of default options assigned to a symbol. Options[expr] gives the options explicitly specified in a particular expression such as a graphics ...

All expressions in Mathematica are ultimately built from a small number of distinct types of atomic elements.

NDSolve solves a differential equation numerically. It returns solutions in a form that can be readily used in many different ways. One typical use would be to produce a plot ...

The flexibility of Mathematica's symbolic architecture is reflected in its rich collection of carefully defined constructs for localization and modularization. The use of ...

The solution given by DSolve can be verified using various methods. The easiest method involves substituting the solution back into the equation. If the result is True, the ...

Ticks is an option for graphics functions that specifies tick marks for axes.