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.