| 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.[http://en.wikipedia.org/wiki/Plane_%28geometry%29] | | 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.[http://en.wikipedia.org/wiki/Plane_%28geometry%29] |