Y-intercept
In analytic geometry, using the common convention that the horizontal axis represents a variable "x" and the vertical axis represents a variable "y", a "y"-intercept or vertical intercept is a point where the graph of a function or relation intersects the "y"-axis of the coordinate system. As such, these points satisfy "x" = 0. Using equations. If the curve in question is given as formula_1 the "y"-coordinate of the "y"-intercept is found by calculating formula_2 Functions which are undefined at "x" = 0 have no "y"-intercept. If the function is linear and is expressed in slope-intercept form  as formula_3 the constant term formula_4 is the "y"-coordinate of the "y"-intercept. Multiple y-intercepts. Some 2-dimensional mathematical relationships such as circles, ellipses, and hyperbolas can have more than one "y"-intercept. Because functions associate "x" values to no more than one "y" value as part of their definition, they can have at most one "y"-intercept. x-intercepts. Analogously, an "x"-intercept is a point where the graph of a function or relation intersects with the "x"-axis. As such, these points satisfy "y"=0. The zeros, or roots, of such a function or relation are the "x"-coordinates of these "x"-intercepts. Unlike "y"-intercepts , functions of the form "y" = "f"("x") may contain multiple "x"-intercepts. The "x"-intercepts of functions, if any exist, are often more difficult to locate than the "y"-intercept, as finding the y intercept involves simply evaluating the function at "x"=0. In higher dimensions. The notion may be extended for 3-dimensional space and higher dimensions, as well as for other coordinate axes, possibly with other names. For example, one may speak of the "I"-intercept of the current–voltage characteristic of, say, a diode. (In electrical engineering, "I" is the symbol used for electric current.)