Perimeter of Ellipse

[Valentin Albillo]

(04-12-2023 05:43 AM)Werner Wrote:  Look closely, Bob, [...]

Correct. The proper way to unambiguously show Pi would be like this: \(\pi\)

Quote:And I'm afraid to say that any mathematical formula that requires degrees mode for the arcsin is suspicious, to say the least. [...] So not even a very good approximation..

Indeed. The OP says his formula is exact but nothing could be further from the truth. Computing the perimeter of a generic ellipse exactly requires, well, elliptic functions, not elementary functions such as inverse trigonometric ones.

V.