[futurebasic] Re: [FB] [x-fb] Trig functions for ellipses

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From: Joe Lewis Wilkins <PepeToo@...>
Date: Fri, 20 Aug 1999 00:12:58 -0700
Mark wrote:

<I'd like to write a program that draws sine waves that are based on
<ellipses instead of circles.  I'm strong in math but my actual
<background is quite weak.  Does anyone know if there's a topic in math
<that deals with this?  Any code?  All help will be appreciated.  Thanks
<in advance.

Hi Mark,

I was kind of hoping that someone else would respond before I displayed my
innate ignorance, but such was not to be the case.

Two comments. First thanks for sending me to my math books; I found a business
card for which I've been looking forever. The card is Joe Dimaggio Jr's. (not
the Yankee Clipper's son though) who is one of the world's top 50 chefs. He has
recipes of which you can only dream (and salivate) and, hopefully, I'm doing
some Cook Book CDs with him. Not being a gormet anything myself, I didn't think
much of this until my youngest sister told me HOW MANY COOK BOOKS SHE HAS.
Apparently there is an "insatiable" market for this product.

 Second; Your request fascinates me. As an architect, anything dealing with
shapes really catches my attention. First of all, why - assuming you are able to
do this - would you want to do something like this? The general equation for a
circle with the center at the origin is:  x^2 + y^2 = r^2; and for an ellipse:
x^2/a^2 + y^2/b^2 = 1.  Therefore...

For a given x and y there can be only 1 circle; but it seems to me that there
could be a whole multitude of ellipses; so it would seem to me that (if you can
do it at all) you would have to have a sine wave based on a specific ellipse
rather than on a general one as you might with a circle.

Will someone please get me out of this with some dignity?

Joe Wilkins