Abscissa and ordinate Abscissa and ordinate In mathematics, the abscissa (; plural "abscissae" or "abscissæ" or "abscissas") and the ordinate are respectively the first and second coordinate of a point in a coordinate system. The abscissa of a point is the signed measure of its projection on the primary axis, whose absolute value is the distance between the projection and the origin of the axis, and whose sign is given by the location on the projection relative to the origin (before: negative; after: positive). The ordinate of a point is the signed measure of its projection on the secondary axis, whose absolute value
Graph of a function continuous function the graph of such a function is a surface. The concept of the graph of a function is generalized to the graph of a relation. To test whether a graph of a relation represents a function of the first variable "x", one uses the vertical line test. To test whether a graph represents a function of the second variable "y", one uses the horizontal line test. If the function has an inverse, the graph of the inverse can be found by reflecting the graph of the original function over the line . In science, engineering, technology, finance, and