SOLUTION: x=-2y^2 whats the directrix focal diameter, and focus

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Question 980374: x=-2y^2
whats the directrix focal diameter, and focus
Answer by macston(5194) About Me  (Show Source):
You can put this solution on YOUR website!
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Standard form for parabola: y%5E2=4ax
Focus is at (a,0)
Directrix at x=-a
Focal diameter is abs%284a%29
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x=-2y^2 Convert to standard form.
-%28x%2F2%29=y%5E2
4%28-1%2F8%29x=y%5E2
a=-1/8
Focus at (-1/8,0)
Directrix at x=1/8
Focal diameter is abs%284%28-1%2F8%29%29=1/2