The document discusses deriving the sine function and tracing trigonometric functions in GeoGebra. It provides steps to create an applet that graphs the sine function and its derivative by tracing the slope of tangents. Additionally, it describes how to construct a circle, point, and arc in GeoGebra that will trace the sine and cosine functions as another point is moved along the circle. The steps change the x-axis to radians and activate tracing to observe the paths of the points tracing sine and cosine.
5. Applet with the
sine function
Create a new point A
on function f.
Hint: Point A can only
be moved along the
function Point A
6. Applet with the
sine function
Create tangent g to
function f through
point A
Hint: Enter command
g: Tangent(A,f) in the
Input bar
Tangent tool
7. Applet with the
sine function
Create the slope of
tangent g using the
Slope tool
Slope tool
8. Applet with the
sine function
Define point
S = (x(A), m).
Hint: x(A) gives you
the x-coordinate of
point A
9. Applet with the
sine function
Connect points A and
S using a segment
Segment tool
10. Applet with the
sine function
Turn on the trace of
point S.
Hint: Right-click point
S (MacOS: Ctrl-click,
tablet: long click) and
select Show Trace
11. Applet with the
sine function
Right-click (MacOS:
Ctrl-click, tablet: long
click) point A and
choose Animation
from the appearing
context menu.
12. Applet with the
sine function
Hint: An Animation
button appears in the
lower left corner of
the Graphics View. It
allows you to either
pause or continue an
animation
13. Applet with the
sine function
Right-Click on the
Graphics View and
Select Graphics... .
15. Tracing the Graphs of Trigonometric Functions
Just like in the previous tutorial, in this tutorial, we use
the Input bar to create mathematical objects particularly a
circle, an arc, and a point that traces the sine and cosine
function. In doing the tutorial, we learn the following:
use the GeoGebra keyboard commands to construct various
geometric objects
use the GeoGebra trace function
change the interval of the x-axis
16. Open GeoGebra and
be sure the Algebra &
Graphics view is
displayed
(Perspectives menu).
To create point A at
the origin, type A =
(0,0) in the Input
bar and press the
ENTER key on your
keyboard
17. Next, to construct a
circle with
center A and radius 1,
type circle[A,1] in
the Input Bar and
press the ENTER key
on your keyboard
18. We fix point A to
prevent it from being
accidentally moved. To
fix the position of
point A, right click on
point A, and then
click Object Properties
from the context
menu.
19. This will display
the Preferences dialog
box.
In Basic tab of
the Preferences dialog
box, click the Fix
Object check box to
check it, then close
the window
29. Be sure that the Show
label check box is
checked and
choose Value from the
drop-down list box.
This will display the
length of arc BC
30. Next, we change the
color of the arc to
make it visible. Click
the Color tab and
choose red (or any
color you want except
black) from the color
palette
31. Click the Style tab,
then adjust the Line
Thickness to 5, then
click the Close button
32. Next, to construct the
point that will trace
the sine wave, we
construct an ordered
pair (d,y(C)) where d is
the arc length
of BC and the y(C) y-
coordinate (or the
sine) of point C. To do
this, type P = (d,y(C)).
33. Move point C along
the circle. What do
you observe?
34. To trace the path
point P, right click
on P and click Trace
on from the context
menu
35. Now, move point C
along the
circumference of the
circle and see the path
of P
36. To create point Q that
will trace the cosine
wave, type Q = (d,x(C))