Coordinates in the Cartesian PlaneDate: 01/21/2005 at 11:22:40 From: Aaron Subject: I need help on my math. How do I get the coordinates for a point on a graph? Date: 01/21/2005 at 20:06:39 From: Doctor Peterson Subject: Re: I need help on my math. Hi, Aaron. Suppose we are shown a graph with a point A marked on it: | 6+ | 5+ | 4+ *A | 3+ | 2+ | 1+ | +---+---+---+---+---+---+-- 0 1 2 3 4 5 6 You draw a vertical line down to the x-axis (the horizontal axis) and see what number you meet there; that is the x-coordinate of the point: | 6+ | 5+ | 4+ *A (3,_) | | 3+ | | | 2+ | | | 1+ | | | +---+---+---+---+---+---+-- 0 1 2 3 4 5 6 Then you draw a horizontal line to the y-axis (the vertical axis), and that number is the y-coordinate of the point: | 6+ | 5+ | 4+-----------*A (3,4) | | 3+ | | | 2+ | | | 1+ | | | +---+---+---+---+---+---+-- 0 1 2 3 4 5 6 To avoid confusion, we always give the coordinates with x followed by y, or (x,y). Therefore, this point is called (3,4), because its x-coordinate is 3 and its y-coordinate is 4. You get to it from the origin, which has coordinates of (0,0), by going right 3 units and up 4 units. If you have any further questions, feel free to write back. - Doctor Peterson, The Math Forum http://mathforum.org/dr.math/ |
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