Section 6: Functions94
To convert form polar (r, θ) coordinates to rectangular x, y coordinates:
  1. Key in the the value for the angle.
  2. Press ENTER  .
  3. Key in the the value for the magnitude r.
  4. Execute P–R (polar to rectangular). The x-coordinate is placed in the X-register and the y-coordinate is placed in the Y-register. To display the y-coordinate value, press X Y .
When you execute the P–R function, the stack contents are changed...
  ...from this...  this.  
T  t
T  t
Z  z
Z  z
Y  angle θ
Y  y-coordinate
X  magnitude r
X  x-coordinate
After you execute R–P or P–R , you can press X Y to place the calculated angle θ or the calculated y-coordinate into the X-register for viewing or further calculation.
For example, convert rectangular coordinates (4,3) to polar form with the angle expressed in radians.