Section 6: Functions87
Keystrokes Display    
XEQ 
  XEQ _ _    
   
ALPHA DEG ALPHA 
  0.0000    
  Sets the HP-41C to degrees mode.
35
  35 _    
   
COS 
  0.8192    
   
Now, find the arc sine in radians of .964
Keystrokes Display    
XEQ 
  XEQ _ _    
   
ALPHA RAD ALPHA 
  0.8192    
  Number remains from previous example. The HP-41C is now in radians mode, the RAD display annunciator is on.
.964
  .964 _    
   
g SIN–1 
  1.3017    
  Radians.
Next, find the tangent of 43.66 grads.
Keystrokes Display    
XEQ 
  XEQ _ _    
   
ALPHA GRAD ALPHA 
  1.3017    
  The HP-41C is now in grads mode and the GRAD display annunciator is on. Number remains from previous example.
43.66
  43.66 _    
   
TAN 
  0.8183    
  Radians.
XEQ 
  XEQ _ _    
   
ALPHA DEG ALPHA 
  0.0000    
  Sets the HP-41C back to degrees mode.
Degrees/Radians Conversions
The D–R (degrees to radians) and R–D (radians to degrees) functions are used to convert angles between degrees and radians. To convert an angle specified in degrees to radians, key in the angle and execute D–R . If you expect to be using these functions regularly, it is a good idea to assign them to the keyboard for execution in USER mode. For example, to change 45 degrees to radians:
Keystrokes Display    
45
  45 _    
   
XEQ 
  XEQ _ _    
   
ALPHA 
       
   
D g –R 
       
   
ALPHA 
  0.7854    
  Radian.