Casio CFX-9970G User manual

Sketch Function
The sketch function lets you draw lines and graphs on an existing
graph.
• Note that Sketch function operation in the STAT, GRAPH,
TABLE, RECUR and CONICS Modes is different from Sketch
function operation in the RUN and PRGM Modes.
10-1 Before Using the Sketch Function
10-2 Graphing with the Sketch Function
Chapter
10

154
10-1 Before Using the Sketch Function
Press !4(Sketch) to display the sketch menu.
STAT, GRAPH, TABLE, RECUR, CONICS Mode
•{Cls} ... {clears drawn line and point}
•{Tang}/{Norm}/{Inv} ... {tangent}/{line normal to a curve}/{inverse graph}
• {Tang}, {Norm}, and {Inv} menus appear only when you display the sketch
menu while in the GRAPH and TABLE Modes.
•{PLOT} ... {plot menu}
•{LINE} ... {line menu}
•{Crcl}/{Vert}/{Hztl} ... {circle}/{vertical line}/{horizontal line}
• {PEN} ... {freehand drawing}
• {Text} ... {comment text}
RUN, PRGM Mode
• {GRPH} ... {graph command menu}
• {PIXL} ... {pixel menu}
• {Test} ... {tests pixel on/off status}
• Other menu items are identical to those in the STAT, GRAPH, TABLE, RECUR,
CONICS Mode menu.
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10-2 Graphing with the Sketch Function
The sketch function lets you draw lines and plot points on a graph that is already
on the screen.
All the examples in this section that show operations in the STAT, GRAPH, TABLE,
RECUR, and CONICS Modes are based on the assumption that the following
function has already been graphed in the GRAPH Mode.
Memory Area Y1 = x(x+ 2)(x– 2)
The following are the View Window parameters used when drawing the graph.
Xmin = –5 Ymin = –5
Xmax = 5 Ymax = 5
Xscale = 1 Yscale = 1
kk
kk
kTangent [Sketch]-[Tang]
This function lets you draw a line that is tangent to a graph at any point.
uu
uu
uTo draw a tangent in the GRAPH or TABLE Mode
Example To draw a line that is tangent to point (x= 2, y= 0) of y= x(x+ 2)
(x– 2)
1. After graphing the function, display the sketch menu and press 2(Tang).
2. Use the cursor keys to move the pointer the position of the point where you
want to draw the line.
3. Press wto draw the line.
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uu
uu
uTo draw a tangent in the RUN or PRGM Mode
The following is the command syntax for drawing a tangent in these modes.
Tangent <graph function>, <x-coordinate>
• Use the variable data (VARS) menu to specify the function to be graphed.
Example To draw a line that is tangent to point (x= 2, y= 0) of y= x(x+ 2)
(x– 2)
1. In the RUN Mode, display the sketch menu, press 2(Tang), and then
perform the following input.
J4(GRPH)1(Y)b,c
2. Press wto draw the tangent line.
kk
kk
kLine Normal to a Curve [Sketch]-[Norm]
With this function you can draw a line that is normal to the curve at a specific
point.
• A line that is normal to the curve at a given point is one that is perpendicular to
the tangent line at that point.
uu
uu
uTo draw a line normal to a curve in the GRAPH or TABLE Mode
Example To draw a line that is normal to the curve at point (x= 2, y= 0) of
y= x(x+ 2)(x– 2)
1. After graphing the function, display the sketch menu and press 3(Norm).
2. Use the cursor keys to move the pointer the position of the point where you
want to draw the line.
10 - 2 Graphing with the Sketch Function
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3. Press wto draw the line.
uu
uu
uTo draw a line normal to a curve in the RUN or PRGM Mode
The following is the syntax for drawing a line normal to a curve in these modes.
Normal <graph function>, <x-coordinate>
• Use the variable data (VARS) menu to specify the function to be graphed.
kk
kk
kGraphing an Inverse Function [Sketch]-[Inv]
This function lets you graph the inverse of the function used to produce your
original graph.
uu
uu
uTo graph an inverse function in the GRAPH or TABLE Mode
Example To graph the inverse of y= x(x+ 2)(x– 2)
After graphing the function, display the sketch menu and press 4(Inv).
• When graphing an inverse function when there is more than one graph function
stored in memory, select one of the functions and then press w.
uu
uu
uTo graph an inverse function in the RUN or PRGM Mode
The following is the syntax for graphing an inverse function in these modes.
Inverse <graph function>
• Use the variable data (VARS) menu to specify the function to be graphed.
• You can only graph the inverse of functions whose graph type is specified as
rectangular coordinate type.
Graphing with the Sketch Function 10 - 2
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10 - 2 Graphing with the Sketch Function
kk
kk
kPlotting Points [Sketch]-[PLOT]
When plotting points on a graph, first display the sketch menu and then press 6
(g) 1(PLOT) to display the plot menu.
• {Plot} ... {plot a point}
• {Pl·On} ... {plot point at specific coordinates}
• {Pl·Off} ... {delete point at specific coordinates}
• {Pl·Chg} ... {switch status of point at specific coordinates}
uu
uu
uTo plot points in the STAT, GRAPH, TABLE, RECUR and CONICS
Modes [Sketch]-[PLOT]-[Plot]
Example To plot a point on the graph of y= x(x+ 2)(x– 2)
1. After drawing the graph, display the sketch menu and press 6(g) 1(PLOT)
1(Plot) to display the pointer in the center of the screen.
2. Use the cursor keys to move the pointer the locations of the points you want to
plot and press wto plot.
• You can plot as many points as you want.
• The current x- and y-coordinate values are assigned respectively to variables
X and Y.
uu
uu
uTo plot points in the RUN or PRGM Mode [Sketch]-[PLOT]-[Plot]
The following is the syntax for plotting points in these modes.
Plot <x-coordinate>, <y-coordinate>
Example To plot a point at (2, 2)
Use the following View Window parameters.
Xmin = –5 Ymin = –10
Xmax = 5 Ymax = 10
Xscale = 1 Yscale = 2

159
1. After entering the RUN Mode, display the sketch menu and perform the
following operation.
!4(Sketch)6(g)
1(PLOT)1(Plot)c,c
2. Press wand the pointer appears on the display. Press wagain to plot a
point.
• You can use the cursor keys to move the pointer around the screen.
• If you do not specify coordinates, the pointer is located in the center of the
graph screen when it appears on the display.
• If the coordinates you specify are outside the range of the View Window
parameters, the pointer will not be on the graph screen when it appears on
the display.
• The current x- and y-coordinate values are assigned respectively to variables
X and Y.
kk
kk
kTurning Plot Points On and Off
[Sketch]-[PLOT]-[Pl·On]/[Pl·Off]/[Pl·Chg]
Use the following procedures to turn specific plot points on and off.
uu
uu
uTo turn plot points on and off in the STAT, GRAPH, TABLE, RECUR
and CONICS Modes
• To turn a plot point on
1. After drawing the graph, display the sketch menu and press 6(g) 1
(PLOT) 2(Pl·On) to display the pointer in the center of the screen.
2. Use the cursor keys to move the pointer to the location where you want to plot
a point and then press w.
• To turn a plot point off
Perform the same procedure as described under “To turn a plot point on” above,
except press 3(Pl·Off) in place of 2(Pl·On).
• To change the on/off status of a plot point
Perform the same procedure as described under “To turn a plot point on” above,
except press 4(Pl·Chg) in place of 2(Pl·On).
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uu
uu
uTo turn plot points on and off in the RUN or PRGM Mode
The following are the syntax for turning plot points on and off in these modes.
• To turn a plot point on
PlotOn <x-coordinate>, <y-coordinate>
• To turn a plot point off
PlotOff <x-coordinate>, <y-coordinate>
• To change the on/off status of a plot point
PlotChg <x-coordinate>, <y-coordinate>
kk
kk
kDrawing a Line [Sketch]-[LINE]
To draw a line on a graph, first display the sketch menu and then press 6(g)
2(LINE) to display the line menu.
• {Line} ...{Draw a line between two plotted points}
• {F·Line} ... {Draw a line}
uu
uu
uTo connect two plotted points with a line in the STAT, GRAPH,
TABLE, RECUR and CONICS Modes [Sketch]-[LINE]-[Line]
Example To draw a line between the two points of inflection on the
graph of y= x(x+ 2)(x– 2)
Use the same View Window parameters as in the example on page
155.
1. After drawing a graph, display the sketch menu and then press 6(g) 1
(PLOT) 1(Plot) to display the pointer in the center of the screen.
2. Use the cursor keys to move the pointer to one of the points of inflection and
press wto plot it.
3. Use the cursor keys to move the pointer to the other point of inflection.
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4. Display the sketch menu and then press 6(g) 2(LINE) 1(Line) to draw
a line to the second dot.
uu
uu
uTo draw a line between any two points in the STAT, GRAPH,
TABLE, RECUR and CONICS Modes [Sketch]-[LINE]-[F·Line]
Example To draw a line between two points of inflection on the graph of
y= x(x+ 2)(x– 2)
1. After drawing a graph, display the sketch menu and then press 6(g) 2
(LINE) 2(F·Line) to display the pointer in the center of the screen.
2. Use the cursor keys to move the pointer to one of the points of inflection and
press w.
3. Use the cursor keys to move the pointer to the other point of inflection and
press wto draw the line.
uu
uu
uTo draw a line in the RUN or PRGM Mode
The following is the syntax for drawing lines in these modes.
F-Line <x-coordinate 1>, <y-coordinate 1>, <x-coordinate 2>, <y-coordinate 2>
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162
kk
kk
kDrawing a Circle [Sketch]-[Crcl]
You can use the following procedures to draw a circle on a graph.
uu
uu
uTo draw a circle in the STAT, GRAPH, TABLE, RECUR and CONICS
Modes
Example To draw a circle with a radius of R = 1 centered at point (1, 0)
on the graph of y= x(x+ 2)(x– 2)
1. After drawing a graph, display the sketch menu and then press 6(g) 3
(Crcl) to display the pointer in the center of the screen.
2. Use the cursor keys to move the pointer to the location where you want the
center point of the circle to be and press wto plot it.
3. Use the cursor keys to move the pointer to a point on the circumference of the
circle (here to point x= 0) and then press wto draw the circle.
uu
uu
uTo draw a circle in the RUN or PRGM Mode
The following is the syntax for drawing circles in these modes.
Circle <center point x-coordinate>, <center point y-coordinate>, <radius R
value>
• Certain View Window parameters can make a circle appear as an ellipse.
10 - 2 Graphing with the Sketch Function