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July 18th, 2017, 05:14 AM   #1
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Post HELP!!!Pre-Calculus Advance study question

1. Find the vertex , the focus , the axis of symmetry and the directrix of the parabola defined by the equation 2y²+8y²+x+1=0

2. Find the vertex , the focus , the axis of symmetry and the directrix of the parabola defined by the equation x²-8x-y+2=0

4. Find an equation of the parabola with focus at (8,0) and directrix x=2

5. The bulb of a flashlight is placed at the focus above the parabolic reflector . if the surface is 5 inches across and 1.5 deep at the vertex , how far is the bulb above the vertex?

6. A ball was thrown upward from ground level . as it rose and eventually fell back to the ground . its path traced a parabola suppose to reached a maximum elevation of 12 ft. And it landed 10 ft away from where it thrown up

P.S: sorry for the bad drawing of the problem in #3


Last edited by Simple; July 18th, 2017 at 05:22 AM.
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July 18th, 2017, 05:45 AM   #2
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Beer soaked question follows.

What have you done so far?
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July 18th, 2017, 12:57 PM   #3
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Only 2 and 3 sir
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July 18th, 2017, 01:23 PM   #4
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Is question 1 typed incorrectly? It has two terms in y².

For questions that refer to the focus or directrix (or similar), this article might help.

Question 6 seems to be incomplete. What are you asked to do?
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July 18th, 2017, 01:31 PM   #5
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Note the attached image ...

1) check the equation you posted ... two $y^2$ terms? If you did (2), you should be able to do (1).

4) vertex is at $(5,0)$ ... $p = 3$

5) sketch a parabola with vertex at the origin ... three points on the parabola $(-2.5,1.5)$, $(0,0)$, and $(2.5,1.5)$
use the equation $y = ax^2$ to determine the value of $a = \dfrac{1}{4p}$

6) three points on the parabola ... $(0,0)$, $(5,12)$, and $(10,0)$.
Now what?

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