Set your viewing window to the principal values for sine by pressing WINDOW
(–)
9 0 ENTER 9 0 ENTER 1 0 ENTER (–)
1 ENTER 1
ENTER 1 ENTER . Press GRAPH to view the graph.
You will first learn how to zoom in to find a solution to the equation. You need
to save this original graph and viewing window by pressing ZOOM , touching
G STO
, and double touching
1 StoWin
. This will allow you to return to this
original screen after zooming in to find the first
x
intercept. Set the zoom
factors by pressing ZOOM , touching
B FACTOR
, pressing ENTER 5 ENTER
5 ENTER . Press GRAPH to exit the menu and return to the graph. These
larger factors will expedite the zooming in or zooming out that you desire to do.
To find the left intercept, press TRACE to engage the trace and move the cursor
near this intercept by continuing to press the key. Your graph should look
like the following one:
Now, press ZOOM , touch
A ZOOM
, and double touch
3 In
to zoom in on the
left intercept and solution of this equation. Press TRACE and to trace near
and approximate the intercept. As the graph below shows, the first solution is
approximately 19.4°.
24
Solving Trigonometric Equations/TRIGONOMETRY USING THE SHARP EL-9600
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