Re: [Phys-L] playing for keeps

[Ludwik Kowalski <kowalskil@mail.montclair.edu>]

On Jun 29, 2013, at 1:26 PM, John Denker wrote:

> 3) Given an ellipse with semi-major axis "b" and semi-minor
>  axis "a", what's the formula for the area of the ellipse?
>  I don't remember this formula, but I can figure it out in
>  less time than it takes to ask the question.

I cannot do this; even for the area of a circle (A=PI*r^2, where PI is the perimeter/diameter, by definition).

The only thing I can do "in less time than it takes to ask the question" is to justify the following answer: "the area of a circle is smaller, pehaps 20% or 30% smaller, than the area of a subscribed square, 4*r^2. 

Ludwik