Perimeter of the Ellipse (HP-15C)

[OlidaBel]

(06-03-2021 09:43 AM)C.Ret Wrote:  HP-15C / HP-11C version:

Code:

001- ►LBL E
002-   STO 0  x↔y  STO+0  x=y?  GTO 1
007-   -  STO 1  STO/0  RCL-1
011-   5  GSB 0  2  GSB 0  2  GSB 0  3  GSB 0  4  GSB 0  3  GSB 0  3  GSB 0  1  GSB 0  1  GSB 0  RCL+0  RCL*1  GTO 2

032- ►LBL 0  4  RCL 0  *  R^  -  /  RTN

040- ►LBL 1  2  *
043- ►LBL 2  PI  *
046- RTN

Usage : a [ENTER^] b [ f ][ E ] returns ellipse perimeter P.

Registers:
R0: \( -y=\frac{a+b}{b-a} \)
R1: \( (b-a) \)

Edited several times to correct english, missing sentences and code typos.

Encore une solution élégante de C.Ret
You play with LBL 1 through LBL 2 without RTN, subtle.
Tested on DM42. I forgot that there was a R^ on 15C.