Solving Trigonometric Equations - Sharp EL-9900C User Manual

SOLVING TRIGONOMETRIC EQUATIONS

To solve a trigonometric equation graphically using the
zoom feature:
1. Turn the calculator on and press Y=
expression. Set the calculator to degree mode by pressing 2ndF
B (DRG) and 1 (Deg). Press 2ndF
2. To find the solutions of 3sin
b
) a 2
3. Set your viewing window to the principal values for sine by pressing
WINDOW
ENTER 1
4. To save this original graph and viewing window, press ZOOM
1 (StoWin).
5. Set the zoom factors by pressing ZOOM
ENTER 5
6. To find the left intercept press TRACE and move the cursor near this
intercept by continuing to press the
7. Now, press ZOOM A (ZOOM) and 3 (In) to zoom in on
the left intercept and solution of this equation. Press TRACE and
trace near and approximate the intercept.
8. Return to the original screen by pressing ZOOM H (RCL) and
1 (RclWin). Trace to find the right intercept.
Advanced Keyboard/TRIGONOMETRY USING THE SHARP EL-9900
Copyright © 2002, Sharp Electronics Corporation. Permission is granted to photocopy for educational use only.
2
x – 4sin x + 1 = 0, press 3
– 4 sin X/θ/T/n
(–)
9 0 ENTER
ENTER 1 ENTER . Press GRAPH to view the graph.
ENTER . Press GRAPH to exit the menu.
CL to access and clear Y1 of an old
QUIT to exit the menu.
+ 1 ENTER .
9 0 ENTER 1
B (FACTOR) ENTER
key.
9
SET UP
( sin X/θ/T/n
(–)
0 ENTER 1
G (STO) and
5
to