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Finding the equation of parabola

jamescv31

New member
Nov 30, 2013
17
Greetings, I‘m trying to analyze the given of directrix x = -1, axis y = 2, and latus rectum as 2

I believe there‘s two possibility equations.

I‘m not sure for finding the vertex since I got between ( -.5, 0) and origin itself.
 

HallsofIvy

Well-known member
MHB Math Helper
Jan 29, 2012
1,151
I presume that, by "latus rectum as 2", you mean that the length of the latus rectum is 2. In a parabola that is always 4 times the distance from the vertex to the focus so that distance is 1/2. that is also the distance from the vertex to the directrix so the vertex must be at (-1+ 1/2, 1)= (-1/2, 1) (with the parabola opening in the positive x direction) or at (-1- 1/2, 1)= (-3/2, 1) (with the parabola opening in the negative x direction).
 
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jamescv31

New member
Nov 30, 2013
17
Yes the length of latus rectum is 2