Question 1187810
Sunday, April 2, 2017
7:06 PM

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The equation of a parabola with a vertical axis is *[tex \Large (x\,-\,h)^2\ =\ 4p(y\,-\,k)], where the vertex is at the point *[tex \Large (h,k)] and *[tex \Large p] is the directed distance from the vertex to the focus.


In this case, since the focus is 100 feet above the vertex at *[tex \Large (0,0)], *[tex \Large p\ =\ 100].  Then, because the vertex is at *[tex \Large (0,0)] you have *[tex \Large h\ =\ 0] and *[tex \Large k\ =\ 0], and you have all  the information you need to write the equation simply by substituting values into the vertex form.


Since the diameter of the antenna is 200 feet, i.e. 100 feet on each side of the vertex, you should specify the domain of your function to be *[tex \Large \[-100,100\]]

																
John
*[tex \LARGE e^{i\pi}\ +\ 1\ =\ 0]
My calculator said it, I believe it, that settles it
*[illustration darwinfish.jpg]

From <https://www.algebra.com/cgi-bin/upload-illustration.mpl> 
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