HP 15c Scientific manual 1718, 006 007 008 009 010-43,30 011 012-43,30 013

Appendix D: A Detailed Look at _ 225

In order to find the first time at which the height is 107 meters, use initial estimates of 0 and 1 second and execute _using B.

Keystrokes Display

¥

0 v 0.0000

11

´ _ 4.1718

B

)	4.1718
)	0.0000

Run mode.

Initial estimates.

The desired root.

A previous estimate of the root. Value of f(t) at root.

It takes 4.1718 seconds for the ridget to reach a height of exactly 107 meters. (It takes approximately two seconds to find this solution.)

However, suppose you assume that the function h(t) is accurate only to the nearest whole meter. You can now change your subroutine to give f(t) = 0 whenever the calculated magnitude of f(t) is less than 0.5 meter. Change your subroutine as follows:

Keystrokes	Display
¥	000-
t“006	006–		30
a	007–	43	16
.	008–		48
5	009–		5
T7	010–43,30, 7
`	011–	43	35
T0	012–43,30, 0
K	013–	43	36

Program mode.

Line before ninstruction. Magnitude of f(t).

Accuracy

Test for x > y and return zero if accuracy > magnitude (0.5 > f(t) ).

Test for x ≠ 0 and restore

f(t) if value is nonzero.