Pre-Calculus/Topics in Analytical Geometry help!

[xzx89724]

I need help with three Pre-Calculus questions.

1. Write an equation for a parabola with a focus of (-1,0) and a vertex of (-1,4)


2. Write an equation in standard form for an ellipse with foci (3,0) and (-3,0) and with y-intercepts 9 and -9.


3. Write an equation for the parabola in standard form, x^2+4x-4y+12=0. The vertex is (-2,2) Focus is (-2,3) directrix is y=1 and axis of symmetry is x=2

Thanks!

 

[tkhunny]

You didn't show any work!

I'll give you a hint on #1.

You should have (y-4) and (x+1) in there somewhere.

 

[xzx89724]

You didn't show any work!

I'll give you a hint on #1.

You should have (y-4) and (x+1) in there somewhere.

Sorry for no work! I honestly didn't have much clue on how to start any of these. I have a formula page handy, but I'm a little uneasy...

 

[xzx89724]

And for #2 I know the Vertex is at 2,-2 Focus at -2,3 Directrix is at y=1 and axis of symmetry is at x=2

 

[HallsofIvy]

And for #2 I know the Vertex is at 2,-2 Focus at -2,3 Directrix is at y=1 and axis of symmetry is at x=2

Then I recommend that you go back and review the basic information about conic sections (or read the problem again)! You were asked about an ellipse that has two foci, four vertices, and two axes of symmetry but does not have a "directrix".

2. Write an equation in standard form for an ellipse with foci (3,0) and (-3,0) and with y-intercepts 9 and -9.

Where is the center of the ellipse? Knowing that, and that the y-intercepts are 9 and -9, where are two of the vertices? What is the "semi-major axis"? Knowing that and that the foci are at (3, 0) and (-3, 0), what is the "semi-minor axis"?