Question 42203
<pre>how do you plot an ordered pair in the cartesian plane?

Let's say you want to plot the ordered pair (4, 7)

Draw an x and y axis like this 

 {{{ graph( 400, 400, -10, 10, -10, 10, 0) }}}

The first coordinate of (4, 7), called the x-coordinate, is 4.

Locate 4 on the x-axis, the horizontal axis, and
draw a vertical line through it, like this:

 {{{ graph( 400, 400, -10, 10, -10, 10, 999(x-4)) }}}

The second coordinate of (4, 7), called the y-coordinate, is 7.

Now locate 7 on the y-axis, the vertical axis, and
draw a horizontal line through it, like this: 

 {{{ graph( 400, 400, -10, 10, -10, 10, 999(x-4), 7) }}}

Draw a dot where these two lines cross:

 {{{ graph( 400, 400, -10, 10, -10, 10, 999(x-4), 7, 7+sqrt(.05-(x-4)^2), 7-sqrt(.05-(x-4)^2)) }}}

Finally erase the two guide lines:

 {{{ graph( 400, 400, -10, 10, -10, 10, 7+sqrt(.05-(x-4)^2), 7-sqrt(.05-(x-4)^2)) }}}

Eventually you won't find it necessary to draw those two lines at all.
So you won't even have to erase them.  Just draw a dot which is directly
above or below the x-coordinate on the x-axis and which is directly to the
right or left of the y-coordinate on the y-axis.

To plot the ordered pair (-5,3)

 {{{ graph( 400, 400, -10, 10, -10, 10, 3+sqrt(.05-(x+5)^2), 3-sqrt(.05-(x+5)^2)) }}}

To plot the ordered pair (-4, -4)

 {{{ graph( 400, 400, -10, 10, -10, 10, -4+sqrt(.05-(x+4)^2), -4-sqrt(.05-(x+4)^2)) }}}

If just one of the coordinates is 0, the point is ON the axis of the
coordinate that is NOT 0.

To plot the ordered pair (0, 6), the 6 is not 0, and it is the y-coordinate
so (6, 0) is ON the y-axis at 6. Look carefully and you'll see it marked
at 6 on the y-axis of the graph below:

 {{{ graph( 400, 400, -10, 10, -10, 10, 6+sqrt(.05-x^2), 6-sqrt(.05-x^2)) }}}


To plot the ordered pair (-5,0), the -5 is not 0, and it is the x-coordinate
so (6, 0) is ON the x-axis at -5.

 {{{ graph( 400, 400, -10, 10, -10, 10, +sqrt(.05-(x+5)^2), -sqrt(.05-(x+5)^2)) }}}

Finally if both coordinates are 0, that is, (0,0), then to plot this ordered
pair, draw a dot where the axes cross.  This special point is called the
"origin".

 {{{ graph( 400, 400, -10, 10, -10, 10, +sqrt(.05-x^2), -sqrt(.05-x^2)) }}} 

Edwin
AnlytcPhil@aol.com</pre>