HP -42S Manual page 15

+/–
RCL 03
√x
–
2
RCL 00
×
÷
And the second root is given by
RCL 01
+/–
RCL 03
√x
+
2
RCL 00
×
÷
So what about if you have to solve hundreds of this kind of equation? Only changing the a, b and c
values? It would be better to save all the steps in the calculator's memory and let it do the calculations
for you. This is what calculator programming is about.
To enter in the program mode you must do
programs yet, you are going to see:
00►{ 0-Byte PRGM} 01 .END.
(If there is a program we can erase it by doing
Now just enter the first sequence starting in RCL 01 x
the end you will have 08 09►STO 03
This means that this part of the program takes 9 lines. You can move through the program lines by
using the ▲▼ cursors (which, of course, cannot be programmed). Two important things to say here
are:
1. The functions are not always shown in the calculators display as we know them. For example
2
the x function is showed as X↑2.
2. We don't need to press ENTER after a number, unless it's between two numbers.
Now let's enter the second part of the program which gives to us the first root. (if you used the cursors
you must go back where you stopped). After doing so we have
17 ×
18►÷
Again in the display the functions are not exactly as we know and √x appears as SQRT.
Unless we store the result in a memory we must find a way to stop the program to see the result. This
is doing by the function STOP which is entered by pressing R/S. (R/S means "run and stop") So after
this we have
PRGM (above the R/S key). If the memory has no
CLEAR CLP before entering in program mode).
2
, etc. Every command will take a line and in