Use your graphing calculator to graph y= ax2 for a = 1 /5, 1, and 5, then again for a =-1 /5, -1, and -5. Copy all six graphs onto a single coordinate system and label each one. Explain how a negative value of a affects the parabola.

System that uses coordinates to uniquely determine the position of points. The most common coordinate system is the Cartesian system, where points are given by distance along a horizontal x-axis and vertical y-axis from the origin. A polar coordinate system locates a point by its direction relative to a reference direction and its distance from a given point. In three dimensions, it leads to cylindrical and spherical coordinates.