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Math Forum » Discussions » Math Topics » geometry.pre-college.independent

Topic: A single term formula for calculating the circumference of ellipse
Replies: 8   Last Post: Jan 6, 2013 3:37 AM

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thomasinventions@yahoo.com

Posts: 35
Registered: 12/23/11
Re: A single term formula for calculating the circumference of ellipse
Posted: Jan 6, 2013 3:17 AM
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This enables an extra significant digit at the worse part of the approximation of Zafary's discovery:

E(1-x^2)~(1+x)*(pi/4)^(1-(1+36x-37x^2)^2/(1+38x+36x^2)^2)

I like to put the circumference of ellipse into terms of E.

C~4a(1+b)(pi/4)^(1-(1+36b-37b^2)^2/(1+38b+36b^2)^2)

Letting b=b/a.

I figure these numbers would be simple to remember.


-Thomas Blankenhorn

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