Figure 4.5: 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. 4.5).

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, use the region tool and click in the desired region of the plane. One must draw all lines defining the region before filling it in. 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 place a point where coordinates are not both integers: use the input field to enter numerical values (fractions and mixed numbers can be placed using the icons beneath the field), then click on the icon with horizontal broken line (for the y-coordinate) or vertical broken line (for the x-coordinate). A broken line will appear on the plane for each given coordinate. Use the pencil to mark the desired point at their intersection. Another method is the click on the ordered pair icon (with a comma separating two boxes in parentheses), enter a pair of coordinates (in terminating decimal, fractional, or mixed-number form), then click on the icon with a small Cartesian plane and a point marked by "X." This will place the point directly on the plane without using the pencil.

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.