| + | In [[mathematics]], a '''plane''' is any flat, two-[[dimensional]] [[surface]]. A plane is the two dimensional analogue of a [http://en.wikipedia.org/wiki/Point_(geometry) point] (zero-dimensions), a [http://en.wikipedia.org/wiki/Line_(geometry) line] (one-dimension) and a [[space]] (three-dimensions). Planes can arise as subspaces of some higher dimensional space, as with the walls of a room, or they may enjoy an independent [[existence]] in their own right, as in the setting of [http://en.wikipedia.org/wiki/Euclidean_geometry Euclidean geometry]. |
| + | When [[working]] in two-dimensional Euclidean space, the definite article is used, the plane, to refer to the whole [[space]]. Many [[fundamental]] tasks in [http://en.wikipedia.org/wiki/Geometry geometry], [http://en.wikipedia.org/wiki/Trigonometry trigonometry], and graphing are performed in two-dimensional space, or in other [[words]], in the plane. A lot of mathematics can be and has been performed in the plane, notably in the areas of geometry, trigonometry, graph theory and graphing. |