- #1

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vertex (-2, 3), focus (0,3)

Find the equation of the parabola.

Dirac.

Find the equation of the parabola.

Dirac.

- Thread starter Dirac
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- #1

- 19

- 0

vertex (-2, 3), focus (0,3)

Find the equation of the parabola.

Dirac.

Find the equation of the parabola.

Dirac.

- #2

lurflurf

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What have you tried so far?Dirac said:vertex (-2, 3), focus (0,3)

Find the equation of the parabola.

Dirac.

Find the directix. then recall

A parabola is the set of point equidistant from the focus and directix.

Last edited:

- #3

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So far I have got to thislurflurf said:What have you tried so far?

Find the directix. then recall

A parabola is the set of point equidistant from the focus and directix.

((y-3)^2)=4a(x+2)

What now

Dirac.

- #4

lurflurf

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a will be the distance between the focus and vertex.Dirac said:So far I have got to this

((y-3)^2)=4a(x+2)

What now

Dirac.

Why is this?

- #5

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How does one find the vertexlurflurf said:a will be the distance between the focus and vertex.

Why is this?

- #6

lurflurf

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you started out withDirac said:How does one find the vertex

vertex (-2, 3), focus (0,3)

The points of a parabola are equidistant from it directrix and focus.

The vertex is the point closest to them. that is

distance(vertex,focus)<=distance(point on parabola,focus)

with equality only when the point is the vertex.

- #7

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Could you just post the answer, or would it get up your backside to post something useful in your lifelurflurf said:you started out with

vertex (-2, 3), focus (0,3)

The points of a parabola are equidistant from it directrix and focus.

The vertex is the point closest to them. that is

distance(vertex,focus)<=distance(point on parabola,focus)

with equality only when the point is the vertex.

Dirac.

- #8

lurflurf

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I already said you a is the distance betweenDirac said:Could you just post the answer, or would it get up your backside to post something useful in your life

Dirac.

vertex (-2, 3), focus (0,3)

here you go

a=sqrt[(0-(-2))^2+(3-3)]

=sqrt[2^2]

a=2

Do you understand why?

Can you find the equation of a parabola with

vertex (0,0), focus (0,-4)

- #9

HallsofIvy

Science Advisor

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How pathetic. Why in the world would anyoneDirac said:Could you just post the answer, or would it get up your backside to post something useful in your life

Dirac.

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