HP 42S manual 19STOP

Page 19

RCL 00 x

÷

So what about if you have to solve more 100 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 calculators programming is about.

To enter in the program mode you must do ▀ PRGM (above R/S key).

If the memory has no program you are going to see:

00►{ 0-Byte PRGM} 01 .END.

(If there is a program we can erase it by doing ▀ CLEAR CLP before entering in program mode)

Now just enter the first sequence starting in RCL 01 x2 , etc.

Every command will take a line and in 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 the x2 function is showed as X↑2. 2-We don't need to press ENTER after a number, unless 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

17x

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

18÷

19►STOP

Finally we enter the last part of the program and after this we have

27x

28►÷

If you move using the cursors you will find .END. in line 29 (which is the end of the program) and in line zero we find 00►{ 31-Byte PRGM }. Almost 1 byte per line of program.

As we said the HP-42S has about 7200 bytes of memory. Not bad! Just for comparison HP-32S had 390 bytes and spend about 1.5bytes per line, HP-20S had only 99 lines/steps and HP-9G has 400 steps while HP-33S has 31KB (but hardly can take advantage of this due to 26 memories/labels limitation, which is the same of 32S, and it spends about 3bytes per line).

After entered the program just press EXIT. Now enter the numbers a, b and c of the equation. For example for the equation x25 x4=0 we enter

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Contents An alternative HP-42S/Free42 Manual Version 2005 Index Introduction RPN Basic OperationsTraining RPN using HP-42S Setting the display contrastTurn ON/OFF FIX, SCI, ENG, ALL, RDX., RDX MenusPage Stack Modes MenuGetting used to some keys of the keyboard Page Abcde Fghi Jklm Nopq Rstuv Wxyz Memory More on the Clear menu Catalog menuAssign FCN ABS Custom menuAssign ABS to Probability Where N!=N.N-1.N-2...2.1Page Complex numbers in rectangular coordinates Complex NumbersComplex numbers in polar coordinates Basic programming Programming19STOP More than one program in the memory X?0 and X?Y sub-menus EnterLBL Prime Real program examplesSqrt Select Solve Program Using the SolverPage Ba f  xdx Numeric IntegrationEnter 6 Σ+ StatisticsSub-menu Cfit Second line ALLΣ, LINΣ, Σreg and ΣRG? Functions Matrices = B Enter Matrix NEWRCL a RCL B Matrix Cross Enter NEW Enter ComplexMatrix 1 Enter 3 NEW Enter 3 NEW Edit 1 Enter →→5 +/- Enter Exit STO BOther Bases Flags License