HP HP-20S - Page 80

The solution requires two calculations of the expression x> — sin x
(for x = x; and for x = x,). Since the solution includes an expression
that must be repeated for both values of x, you can create a subrou-
tine to execute the repeated keystrokes and save space in program
memory. The program assumes that x; x, has been entered be-
fore executing the program and that the calculator is in Radians mode
(le=) (RAD)).
Keys:
Y
(]
[e](BLjC
(s10] 2
(=] (swap]
(s10] 1
(RCL) 2
(xEQ] 5
(RCL] 1
(XEQ] 5
78 6: Programming
Display:
00-
01- 6141 C
02- 21 2
03- 51 31
04- 21 1
05- 71
06- 22 2
07- 415
08- 65
09- 22 1
10- 41 5
11- 74
Description:
Enters Program mode.
Clears program
memory.
Names program “C”.
Stores the displayed
value (x;) in R,.
Swaps (x, for xy).
Stores displayed value
(xl) in Rl'
Clears display so there
is no hidden value or :
annunciator when pro-
gram is complete.
Recalls x,.
Executes subroutine to
calculate x,2 — sin x,.
(X22 - SiI'le) — ...
Recalls x;.
Executes subroutine
again to calculate
X2 — sin xq.
(2 — sin xy) —
(xlz — sin xl).