HP 15c Manual

							 Contents 11 
 
Appendix F: Batteries   .............................................  259 
Low-Power Indication  .......................................................  259 
Installing New Batteries  ................................................  259 
Verifying Proper Operation (Self-Tests)  ...............................  261 
Function Summary and Index  .....................................  262 
Complex Functions  ..........................................................  262 
Conversions  ...................................................................  262 
Digit Entry  ......................................................................  262 
Display Control  ..............................................................  263 
Hyperbolic Functions  .......................................................  263 
Index Register Control  .....................................................  263 
Logarithmic and Exponential Functions  ..............................  263 
Mathematics  ..................................................................  264 
Matrix Functions  .............................................................  264 
Number Alteration  ..........................................................  265 
Percentage  .....................................................................  266 
Prefix Keys  .....................................................................  266 
Probability  .....................................................................  266 
Stack Manipulation  .........................................................  266 
Statistics  ........................................................................  267 
Storage  .........................................................................  267 
Trigonometry  ..................................................................  268 
Programming Summary and Index  ..............................  269 
Subject Index  ...........................................................  271 
  
						

							 
12 
The HP-15C: 
A Problem Solver 
The  HP-15C  Advanced  Programmable  Scientific  Calculator  is  a  powerful 
problem  solver,  convenient  to  carry  and  easy to  hold.  Its  continuous 
memory retains data  and program instructions indefinitely  until  you choose 
to  reset  it.  Though  sophisticated,  it  requires  no  prior  programming 
experience or knowledge of programming languages to use it. 
The  new HP-15C is a  modern re-release  of the  original  HP-15C introduced 
in  1982.  While  the  battery  life  of  the  new  version  is  now  estimated  to  be  1 
year  for  normal  use,  the  calculator  is  now  at  least 150  times  faster  than  the 
original. The  low-power  indicator  gives  you  plenty  of  warning  before  the 
calculator stops functioning. 
The  HP-15C also conserves power by automatically shutting its display off 
if  it  is  left  inactive  for  a  few  minutes.  But  dont  worry  about  losing data – 
any information contained in the HP-15C is saved by Continuous Memory. 
A Quick Look at v 
Your Hewlett-Packard calculator uses a  unique  operating logic, represented 
by  the v key,  that  differs  from  the  logic  in  most  other  calculators. 
You  will  find  that  using v makes  nested  and  complicated 
calculations easier and faster to work out. Lets get acquainted with how this 
works. 
For  example,  lets  look  at  the  arithmetic  functions.  First  we  have  to  get  the 
numbers  into  the  machine.  Is  your  calculator  on?  If  not,  press =.  Is  the 
display  cleared?  To  display  all  zeros,  you  can press | ` that  is,  press 
|, then −.* To perform arithmetic, key in the first number, press v 
to separate the  first number from the second, then key in the second number 
and press +, -, * or ÷. The result appears immediately after you 
press any numerical function key. 
                                                           * If  you  have  not  used an  HP calculator before, you will  notice that  most keys  have three labels.  To  use the primary function – the one printed in white on top of the key – just press that key. For those printed in gold or blue, press the gold ´ key or the blue | key first.   
						

							 The HP-15C: A Problem Solver 13 
 
The  display  format  used  in  this  handbook  is • 4  (the  decimal  point  is 
―fixed‖  to  show  four  decimal  places)  unless  otherwise  mentioned.  If  your 
calculator  does  not  show  four  decimal  places,  you  may  want  to  press 
´• 4 to match the displays in the examples. 
Manual Solutions 
Run through  the  following  two-number  calculations.  It  is  not  necessary  to 
clear the calculator between problems. If you enter a digit incorrectly, press 
− to undo the mistake, then key in the correct number. 
To Compute Keystrokes Display 
9 - 6 = 3 9 v 6 ­ 3.0000 
9 × 6 = 54 9 v 6 * 54.0000 
9 ÷ 6 = 1.5 9 v 6 ÷ 1.5000 
96 = 531,441 9 v 6 Y 531,441.0000 
Notice that in the four examples: 
 Both numbers are in the calculator before you press the function key. 
 v is used only to separate two numbers that are keyed in one 
after the other. 
 Pressing a numeric function key, in this case ­ * ÷ or Y, 
executes the function immediately and displays the result. 
To  see  the  close  relationship  between  manual  and  programmed  problem 
solving, lets first calculate the solution to a problem manually, that is, from 
the keyboard. Then well use a program to calculate the solution to the same 
problem with different data.  
						

							14 The HP-15C: A Problem Solver 
 
The time an object takes to fall to the ground (ignoring air friction) is given 
by the formula 
, 
where  t = time in seconds, 
h = height in meters, 
g = the acceleration due to gravity, 
9.8 m/s2. 
Example: Compute  the  time  taken  by a 
stone  falling  from  the  top  of  the  Eiffel 
Tower (300.51 meters high) to the earth. 
Keystrokes Display  
300.51 v 300.5100 Enter h. 
2 * 601.0200 Calculates 2h. 
9.8 ÷ 61.3286 (2h) /g. 
¤ 7.8313 Falling time, seconds. 
Programmed Solutions 
Suppose  you  wanted  to  calculate  falling  times  from  various  heights.  The 
easiest  way  is  to  write a program  to  cover  all  the  constant  parts  of  a 
calculation and provide for entry of variable data. 
Writing  the  Program. The  program  is  similar  to  the  keystroke  sequence 
you used above. A label is useful to define the beginning of a program, and 
a  return  is  useful  to  mark  the  end  of  a  program.  Also,  the  program  must 
accommodate the entry of new data. 
Loading  the  Program. You  can  load  a  program  for  the  above  problem  by 
pressing  the  following  keys  in  sequence.  (The  display  shows  information 
which you can ignore for now, though it will be useful later.) g
2ht   
						

							 The HP-15C: A Problem Solver 15 
 
 
Keystrokes Display 
|¥ 000- Sets HP-15C to Program 
mode. (PRGM 
annunciator on.) 
´ CLEAR M 000- Clears program memory. 
(This step is optional 
here.) 
´bA 001-42,21,11 Label A defines the 
beginning of the 
program. 
2 002-       2  
* 003-      20  
9 004-       9  
  The same keys you 
  pressed to solve the  
. 005-      48 problem manually. 
8 006-       8  
÷ 007-      10  
¤ 008-      11  
|n 009-   43 32 ―Return‖ defines the end=
of the programK=
|¥ 7.8313 Switches to Run mode. 
(No PRGM 
annunciator.) 
Running  the  Program. Enter  the  following  information  to  run  the 
program. 
Keystrokes Display  
300.51 300.51 Height of the Eiffel Tower. 
´A 7.8313 Falling time you calculated 
earlier. 
1050 ´A 14.6385 The time (seconds) for a stone 
to reach the ground after release 
from a blimp 1050 m high.  
						

							16 The HP-15C: A Problem Solver 
 
With this  program  loaded,  you  can  quickly  calculate  the  time  of  descent  of 
an  object  from  different  heights.  Simply  key  in  the  height  and  press 
´A. Find  the  time  of  descent  for  objects  released  from  heights  of    
100 m, 2 m, 275 m, and 2,000 m. 
The answers are: 4.5175 s; 0.6389 s; 7.4915 s; and 20.2031 s. 
That  program was  relatively  easy.  You  will  see  many  more  aspects  and 
details of programming in part II. For now, turn the page to take an in-depth 
look at some of the calculators important operating basics.  
						

							 
 
 
 
 
Part l 
HP-15C 
Fundamentals  
						

							 
18 
Section 1 
Getting Started 
Power On and Off 
The = key  turns  the  HP-15C  on  and  off.* To  conserve  power,  the 
calculator automatically turns itself off after a few minutes of inactivity. 
Keyboard Operation 
Primary and Alternate Functions 
Most  keys  on  your  HP-15C  perform  one  primary  and  two  alternate,  shifted 
functions.  The  primary  function  of  any  key  is  indicated  by  the  character(s) 
on  the  face  of  the  key.  The  alternate  functions  are  indicated  by  the  gold 
characters  printed  above  the  key  and  the  blue  characters  printed  on  the 
lower face of the key. 
 To select the primary function printed on 
the face of a key, press only that key. For 
example: ÷. 
 To select the alternate function printed in 
gold or blue, press the like-colored prefix 
key (´ or |) followed by the function 
key. For example: ´ _; | 
£. 
Throughout this handbook, we  will observe certain conventions in referring 
to alternate functions. References to the function itself will appear as just the 
key  name  in  a  box,  such  as  ―the W function.‖  References  to the  use  of 
the  key will include  the  prefix key,  such as  ―press | W.‖  References 
to  the  four  gold  functions  printed  under  the  bracket  labeled  ―CLEAR‖  will 
be preceded by the  word ―CLEAR‖, such as the CLEAR Q function,‖ 
or ―press ´ CLEAR M.‖ 
                                                           * Note that the = key is lower than the other keys to help prevent its being pressed inadvertently.  
						

							 Section 1: Getting Started 19 
 
Notice  that  when  you  press  the ´ or | 
prefix  key,  an f or g annunciator  appears 
and  remains  in  the  display  until  a  function 
key is pressed to complete the sequence. 
Prefix Keys 
A  prefix  key is any  key  which  must  precede  another  key  to  complete  the 
key  sequence  for  a  function.  Certain  functions  require  two  parts:  a  prefix 
key and a digit or other key. For your reference, the prefix keys are: 
 ^ • G f > i O 
m ´ | P I l F T 
s ? t H b < _ X 
If  you  make  a  mistake  while  keying  in  a  prefix  for  a  function,  press ´ 
CLEAR u to cancel the error. The CLEAR u key is also used 
to  show  the  mantissa  of  a  displayed  number,  so  all  10  digits  of  the  number 
in the display will appear for a moment after the u key is pressed. 
Changing Signs 
Pressing “ (change  sign) will  change  the  sign  (positive  or  negative)  of 
any  displayed  number.  To  key  in a  negative  number,  press “ after  its 
digits have been keyed in. 
Keying in Exponents 
‛ (enter exponent) is used  when keying in a  number  with an exponent. 
First key in the mantissa, then press ‛ and key in the exponent. 
For  a  negative  exponent  press “ after keying  in  the  exponent.* For 
example,  to  key  in  Plancks  constant  (6.6262×10-34 Joule-seconds)  and 
multiply it by 50: 
                                                           * “ may also be pressed after ‛ and before the exponent, with the same result (unlike the mantissa, where digit entry must precede “). 
0.0000  f  
						

							20 Section 1: Getting Started 
 
 
Keystrokes Display  
6.6262 6.6262  
‛ 6.6262    00 The 00 prompts you to 
key in the exponent. 
3 6.6262    03 (6.6262×103). 
4 6.6262    34 (6.6262×1034). 
“ 6.6262   -34 (6.6262×10-34). 
v 6.6262   -34 Enters number. 
50 * 3.3131   -32 Joule-seconds. 
Note: Decimal digits from the mantissa that spill into the exponent 
field  will disappear from the  display  when  you press ―, but  will be 
retained internally. 
To  prevent  a  misleading  display  pattern, ‛ will  not  operate  with  a 
number having more than seven digits to the left of the radix mark (decimal 
point), nor with a mantissa smaller than 0.000001. To key in such a number, 
use  a  form  having a  greater  exponent  value  (whether  positive  or  negative). 
For  example,  123456789.8×1023 can  be  keyed  in  as  1234567.898×1025; 
0.00000025×10-15 can be keyed in as 2.5×10-22. 
The “CLEAR” Keys 
Clearing means  to  replace  a  number  with  zero.  The  clearing  operations  in 
the HP-15C are (the table is continued on the next page): 
 
Clearing Sequence Effect 
|` Clears display (X-register). 
−  
In Run mode: Clears last digit or entire display. 
In Program mode: Deletes current instruction. 
´ CLEAR ∑ Clears statistics storage registers, display, 
and the memory stack (described in 
section 3).