Subject: Re: Parabola and its focus
Date: Tue, 8 Jul 1997 21:27:21 -0400
From: Alexander Bogomolny

Ronald:

Your equation is incorrect. Parabola's focus is at the point F(0, 1/2), right? The line through P and F is given by

(x-2t)/(2t) = (y-2t2)/(2t2-.5)

which simplifies to

4tx2 -2(4t2-1)x - 4t = 0

with two roots: 2t and -1/(2t). So that your book is correct.

Best
Alexander Bogomolny

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