Sharp EL-9900 - Manual (Page 117)

2
Advanced Keyboard/TRIGONOMETRY USING THE SHARP EL-9900
Copyright © 2002, Sharp Electronics Corporation. Permission is granted to photocopy for educational use only.
Steps for evaluating sin 45° directly
1. Turn the calculator on and press to access the computation screen.
2. Press CL to clear the viewing window of any old expressions.
3. Set the calculator to operate in degrees by pressing 2ndF SET UP
B (DRG) 1 (Deg). Press 2ndF QUIT to exit the menu.
4. Enter and evaluate the expression by pressing sin 4 5 ENTER .
Steps for approximating sin ( ) graphically
1. Press Y= followed by CL to clear an old expression for Y1.
2. Enter the function sin x by pressing sin X/
θ/T/n . Set the calculator to
radian mode by pressing 2nd F SET UP B (DRG) and 2 (Rad). Press
2nd F QUIT to exit the menu.
3. View the graph by pressing ZOOM E (TRIG) 1 sin x.
4. Now, engage the trace by pressing TRACE and tracing near x = = 1.047.
5. With the cursor located near x = 1.047, you can zoom in to find a better
approximation for the y value. Press ZOOM A (ZOOM) 3 (In) to zoom
in on the cursor.
6. Once again, trace over near x = 1.047. Zoom in one more time to see an even
better approximation. The y value of .866 approximates sin ( )..
EVALUATING TRIGONOMETRIC FUNCTIONS
Ч
+ –
ч
π
3
π
3
π
3