Relative extrema – Sharp EL-9900 User Manual
Page 82
7
Advanced Keyboard/CALCULUS USING THE SHARP EL-9900
Copyright © 2002, Sharp Electronics Corporation. Permission is granted to photocopy for educational use only.
1.
Set the graphing calculator to rectangular graphing by pressing 2ndF
SET UP
E (COORD) 1 (Rect). Press 2ndF QUIT to exit the SET UP
menu.
2.
Consider f(x) = 2x
3
– 7x
2
– 70x + 75. Press Y= CL to access and clear Y1.
Press ENTER CL to clear additional Y prompts. Enter f(x) for Y1 by
pressing 2 X/
θ/T/n a
b
3 – 7 X/
θ/T/n x
2
– 7 0 X/
θ/T/n
+ 7 5 .
3.
Graph the function by pressing WINDOW (–) 1 0 ENTER 1 0 ENTER
1 ENTER ZOOM A (Zoom) 1 (Auto).
4.
To determine the point at which the relative maximum occurs, press
2ndF CALC 4 (Maximum). The maximum occurs at x = -2.44.
5.
Find the point at which the relative minimum occurs by pressing 2ndF
CALC 3 (Minimum). The minimum occurs at x = 4.776.
6.
Combining this information with a view of the graph, we see that f(x) is
increasing for x = -
∞ to -2.4427 and from 4.776 to ∞ while f(x) is decreasing
for x between -2.4427 and 4.776.
RELATIVE EXTREMA
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