





4.9 The Answer Editor for Graphing
Figure 4.4: The Answer Editor for Graphing
The Answer Editor for graphing consists of a Cartesian plane with
x and
y coordinate axes and a selection of
other tools for graphing lines and regions of the plane
(Fig. 4.4).

To graph a line, use the pencil tool to plot two points. Then, align
the straightedge (ruler) on the two points (it is a "grabby" tool and
will jump to a point when it is near it). Then use the pencil tool to
draw the line. Note that the effect of the straightedge continues past
its ends, so there is no need to move it to make a line going from edge
to edge of the depicted plane. The line should be started within the
graph area, however.


To fill in a region, first, draw all the lines defining the region. Then
use the region tool and click in the desired region of the plane. In
order for one or more of the lines defining a region to be dotted (as
in the graph of a system containing one or more strict inequalities),
click on the line with the dotted line tool. This may be done before
or after the region is filled.


To draw a graph, use the pencil tool to plot a point. Then, click on
the Plot point button twice.


To plot a point where the coordinates are nonintegers, use the Plot
point button. Using the keyboard, type the numerical values into the
coordinate boxes and click Plot point.


To draw a graph requiring an asymptote, use the asymptote tool (broken
horizontal or vertical line) to place the asymptote as needed. A slanted
asymptote may be placed by first drawing two points and then using the
tool with a broken diagonal line. Plot the additional points needed for
the graph, and then click on the graph button (curved line connecting
"X"s).


For each type of conic section, there is a special tool allowing the
construction of its graph. Normally, the user clicks once with the
tool to establish the center or vertex of the graph, and then one or
more additional times to determine its final form.


As with the numberline, select the eraser tool and click on any part of a
line, arc, or other component to remove it.





