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HP 15c User Manual

Page 190

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190 Section 13: Finding the Roots of an Equation

Keystrokes

Display

-

003–

30

*

004–

20 (x – 6) x.

8

005–

8

+

005–

40

*

007–

20 ((x – 6) x + 8) x.

4

008–

4

*

009–

20 4 ((x – 6) x + 8) x.

7

010–

7

.

011–

48

5

012–

5

-

013–

30

|n

014–

43 32

It seems reasonable that either a tall, narrow box or a short, flat box could
be formed having the desired volume. Because the taller box is preferred,
larger initial estimates of the height are reasonable. However, heights
greater than 2 decimeters are not physically possible (because the metal is
only 4 decimeters wide). Initial estimates of 1 and 2 decimeters are
therefore appropriate.

Find the desired height:

Keystrokes

Display

| ¥

Run mode.

1

v

1.0000

Initial estimates.

2

2

´ _ 3

1.5000

The desired height.

)

1.5000

Previous estimate.

)

0.0000

f(x) at root.