Section 6: Functions78
Keystrokes Display    
g CLX 
  0.0000
   
1.0973731
  1.0973731 _
   
EEX 7
  1.0973731 – 7 _
  Rydberg constant.
CHS 
  1.0973731 – 7 _
  Sign of the exponent is changed
CHS 
  1.0973731 – 7 _
  Sign of the exponent is changed back again.
Rounding a Number
As you know, when you change the display formats with one of the display control functions ( FIX , SCI , or ENG ), the number maintains its full value (10 digits multiplied by a two-digit exponent of 10) no matter how many digits you see. When you execute the RND (round) function, however, the number that is in the display becomes the actual number in the calculator. For example, round the Rydberg constant, now in the display, to two digits beyond the decimal point in SCI format.
Keystrokes Display    
 
  1.0973731   7 _
  Rydberg constant still in X-register.
g SCI 2
  1.10   07
  The display format. Remember, the number in the HP-41C is still in its full-accuracy form internally.
XEQ 
  XEQ _    
  The HP-41C prompts: Execute what?
ALPHA RND ALPHA 
  1.10   07
  The RND function is executed.
g SCI 6
  1.100000   07
  The SCI 6 display shows that the number has been rounded internally.
g FIX 4
  11,000,000.00    
  Display mode set to FIX 4.
Absolute Value
Some calculations require the absolute value, or magnitude, of a number. To obtain the absolute value of the number in the X-register, execute the ABS function. For example, to calculate the absolute value of –3:
Keystrokes Display    
3 CHS 
– 3 _    
   
XEQ 
– XEQ _ _    
   
ALPHA ABS ALPHA 
– 3.0000    
  | –3 |.