Re: circumference of an ellipse
- To: mathgroup at smc.vnet.net
- Subject: [mg19304] Re: circumference of an ellipse
- From: dennisw555 at aol.com (DennisW555)
- Date: Sat, 14 Aug 1999 01:45:24 -0400
- Organization: AOL http://www.aol.com
- References: <7p017c$778@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
>I made a little spreadsheetfile to calculate the circumference (length)
>of
>an ellipse using an iterative process.
>When I compare the results with the results of a formula to approximate
>the
>lenght
> - which is pi(3(a+b)-sqrt((a+3b)(3a+b))) - the difference is greater then
>I
>expected (a few percents).
>This may be a shortcoming of the approximation formula, or of my
>worksheetformulae.
>Could someone please give me the exact results (in 10 or 15 digits) of some
Here are some results I got
a=1, b=1, circ = 6.28318530717958647702
a= 2, b=1, circ=9.68844822054767619828
a=4, b=1, circ=17.1568435503136684457
a=8, b=1, circ=32.7449566001955006842
a=16, b=1, circ=64.4579248618360700975
Hope this helps. Note, the first is for a circle of radius 1.
Dennis