HP 15c Collector's Edition

94 Section 8: Program Branching and Controls
Keystrokes
Display
l * 1
010-45,20, 1
Recall multiplication with the
contents of R
1
(N
0
), yielding
N
t
, the mCi of
131
I remaining
after t days.
´ ©
011- 42 31
Pauses to display N
t
.
l 2
012- 45 2
Recalls limit value to X-
register.
| T 9
013-43,30, 9
x ≥ y? Tests whether limit
value (in X) meets or exceeds
N
t
(in Y).
| n
014- 43 32
If so, program ends.
3
015- 3
If not, program continues.
O + 0
016-44,40, 0
Adds 3 days to t in R
0
.
t A
017- 22 11
Go to “A” and repeat
execution to find a new N
t
from a new t.
Notice that without lines 012 to 014, the loop would run indefinitely (until
stopped from the keyboard).
Let’s run the program, using t
1
= 2 days, N
0
= 100 mCi, and a limit value of
half of N
0
(50 mCi).
Keystrokes
Display
| ¥ Run mode (display will vary).
2 O 0
2.0000
t
1.
100 O 1
100.0000
N
0
.
50 O 2
50.0000
Limit value for N
t
.
´ A
2.0000
t
1.
84.0896
N
1
.
5.0000
t
2.
64.8420
N
2
.
8.0000
t
3.
50.0000
N
3
.
50.0000
N
t
limit; program ends.