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Evaluating limits – Sharp EL-9900 User Manual

Page 76

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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 calculator to floating point decimal display by pressing 2ndF

SET UP C (FSE) and 1 (Float Pt). Set the calculator to rectangular

coordinates E (COORD) and 1 (Rect). Press 2ndF QUIT to exit the

set up menu.

2.

Consider the function f(x) = . Press Y= CL to access and clear the

Y1 prompt. Press ENTER CL to clear the remaining prompts.

3.

Construct a graph of f(x) in the Decimal viewing window by first entering

Y1= with the keystrokes a/b 2 X/

θ/T/n + 2 X/θ/T/n

x

2

– 1 , and then press ZOOM A (ZOOM) 7 (Dec) to see

the graph.

4.

Notice that even though is not defined at x = -1 (as evidenced by the

hole in the graph at that point), the functional values appear to be getting

closer and closer to -1. A careful observation of the graph leads to the

following estimates:

lim f(x) = 0,

x

→ -∞

lim f(x) = -1,
x

→ -1

lim f(x) does not exist,
x

→ 1

and lim f(x) = 0.

x

→ ∞

5.

It also appears that the line y = 0 is a horizontal asymptote and the line x = 1

is a vertical asymptote for this function.

EVALUATING LIMITS

(2x + 2)

(x

2

– 1)

(2x + 2)
(x

2

– 1)

(2x + 2)
(x

2

– 1)