Coordinates of Two PointsDate: 04/23/2002 at 23:21:25 From: Taylor Subject: Seeing Things Graphically (Coordinates) Dear Dr. Math, My teacher asked for the coordinates of two points that lie on the x-axis. I figured that all points on the x-axis must have an x-coordinate of 0, so I wrote (0,4) and (0,98). My friend says that points on the x-axis actually have a y-coordinate of 0. That sounds pretty silly to me. If my friend is right, why would they call it the x-axis? Taylor Date: 04/24/2002 at 08:56:15 From: Doctor Peterson Subject: Re: Seeing Things Graphically (Coordinates) Hi, Taylor. The x-axis is the axis along which the x coordinate CHANGES, while the y coordinate stays zero. Y ^ | (x,y) y +----o | | | | +----+--->X x We assign coordinates to points in the plane by choosing two perpendicular lines and labeling points along each axis with coordinates. The coordinates of any point are found by dropping perpendiculars from the point to the two axes; its x-coordinate is the location along the x-axis where the perpendicular meets. For any point on the x-axis, the perpendicular to the y-axis lands at the origin, so its y-coordinate is zero. - Doctor Peterson, The Math Forum http://mathforum.org/dr.math/ |
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