Sharp EL-9900 - Manual (Page 118)

3
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 sec ( ) directly in degree mode
1. Press to enter computation mode.
2. Press 2ndF SET UP to verify the calculator is in degree mode. If it is not,
change it to degree mode. Press 2ndF QUIT to exit the menu.
3. Enter and evaluate the expression by pressing MATH A (CALC)
0 9 (sec) 2ndF
π a/b 4 MATH E (ANGLE) 4 (r) and
pressing ENTER .
Steps for approximating tan 20° graphically
1. Press Y= and press CL to remove an old expression for Y1.
2. Press 2ndF SET UP to verify the calculator is in degree mode. If it is not,
change it. Press 2ndF QUIT to exit the menu.
3. Enter the function tan x for Y1 by pressing tan X/
θ/T/n .
4. Instead of graphing the function in the default viewing window for tangent,
press WINDOW adjust the Xmin and Xmax to 10° and 30° (value of interest
± 10° ) respectively to start out closer to the value of interest. Set the Xscl =
1. Press ZOOM A (ZOOM) and 1 (Auto) to view the graph.
5. Now, engage the trace by pressing TRACE . Notice the tracer appears at
x = 20° since it is the middle of the x values. The approximate for tan 20°
is .36397.
EVALUATING TRIGONOMETRIC FUNCTIONS
π
4
Ч
+ –
ч
▼