Casio FX-9750G 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, TA-
BLE, RECUR and CONICS Modes is different from Sketch func-
tion operation in the RUN and PRGM Modes.
10-1 Before Using the Sketch Function
10-2 Graphing with the Sketch Function
Chapter
10

174
10-1 Before Using the Sketch Function
Press !4(Sketch) to display the sketch menu.
STAT, GRAPH, TABLE, RECUR, CONICS Mode
!4(Sketch)
1(Cls) ......... Clears drawn line and point
2(Tang)....... Tangent
3(Norm)...... Line normal to a curve
4(Inv).......... Inverse graph
6(g) ........... Next menu
•2(Tang), 3(Norm), and 4(Inv) appear only when you display the sketch
menu while in the GRAPH and TABLE Modes.
6(g)
1(PLOT) ..... Plot menu
2(LINE) ...... Line menu
3(Crcl) ........ Circle
4(Vert) ........ Vertical line
5(Hztl) ........ Horizontal line
6(g) ........... Next menu
6(g)
1(PEN) ....... Freehand drawing
2(Text) ........ Comment text
6(g) ........... Previous menu
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RUN, PRGM Mode
!4(Sketch)
5(GRPH) .... Graph command menu
6(g)
6(g)
3(PIXL)....... Pixel menu
4(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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Before Using the Sketch Function 10 - 1
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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 func-
tion 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
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).
!4(Sketch)2(Tang)
2. Use the cursor keys (f, c, d, e) to move the pointer the position of the
point where you want to draw the line.
e~ e
3. Press wto draw the line.
w

177
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. Enter the RUN Mode, display the sketch menu, and then perform the following
input.
!4(Sketch)2(Tang)
J4(GRPH)
1(Y)b,c
2. Press wto draw the tangent line.
w
kk
kk
kLine Normal to a Curve
With this function you can draw a line that is normal to the curve at a specific point.
• Aline 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).
!4(Sketch)3(Norm)
Graphing with the Sketch Function 10 - 2
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2. Use the cursor keys (f, c, d, e) to move the pointer the position of the
point where you want to draw the line.
e~ e
3. Press wto draw the line.
w
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
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).
!4(Sketch)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.
10 - 2 Graphing with the Sketch Function
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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.
kk
kk
kPlotting Points
When plotting points on a graph, first display the sketch menu and then press 6
(g) 1(PLOT) to display the plot menu.
6(g)1(PLOT)
1(Plot) ........ Plot a point
2(Pl•On) ..... Plot point at specific coordinates
3(Pl•Off) ..... Delete point at specific coordinates
4(Pl•Chg) ... Switch status of point at specific coordinates
uu
uu
uTo plot points in the STAT, GRAPH, TABLE, RECUR and CONICS
Modes
Example To plot a point on the graph of y= x(x+ 2)(x– 2)
1. After graphing the function, display the sketch menu and perform the following
operation to cause the pointer to appear on the graph screen.
!4(Sketch)6(g)1(PLOT)1(Plot)
2. Use the cursor keys (f, c, d, e) 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.
e~ ef ~ f
w
• The current x- and y-coordinate values are assigned respectively to variables X
andY.
Graphing with the Sketch Function 10 - 2
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uu
uu
uTo plot points in the RUN or PRGM Mode
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
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.
ww
• You can use the cursor keys (f, c, d, e) 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 param-
eters, the pointer will not be on the graph screen when it appears on the dis-
play.
• The current x- and y-coordinate values are assigned respectively to variables X
andY.
10 - 2 Graphing with the Sketch Function
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kk
kk
kTurning Plot Points On and Off
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 a graph, display the sketch menu and then perform the following
operation to make the pointer appear at the center of the screen.
!4(Sketch)6(g)1(PLOT)2(Pl•On)
2. Use the cursor keys (f, c, d, e) to move the pointer to the location where
you want to plot a point and then pressw.
• 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).
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>
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kk
kk
kDrawing a 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.
6(g)2(LINE)
1(Line)........ Draw a line between two plotted points
2(F•Line) .... Draw a line
uu
uu
uTo draw a line between two plotted points in the STAT, GRAPH,
TABLE, RECUR and CONICS Modes
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
176.
1. After graphing the function, display the sketch menu and perform the following
operation to cause the pointer to appear on the graph screen.
!4(Sketch)6(g)1(PLOT)1(Plot)
2. Use the cursor keys (f, c, d, e) to move the pointer to one of the points of
inflection and press wto plot it.
d~ df ~ f
w
3. Use the cursor keys to move the pointer to the other point of inflection.
e~ ec ~ c
10 - 2 Graphing with the Sketch Function
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