Easy Parabola Q (1 Viewer)

LoveHateSchool

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From a trial.

Find eqn of the parabola vetex (-1,1) and focus (-3, 1)

Answers say (y-1)^2 = 8(x+3)

I understand it is a left facing parabola, and the directrix is x=1 and all that, so I thought the answer would be (y-1)^2=-8(x+1). Confused if they have mistakingly used the focus coordinates instead of the vertex, or am I failing at a very simple Q :p
 

gr_111

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no, your answer is correct for the vertex and focus you specified.

The answer they have given swaps the co-ordinates of the vertex and the focus. i.e. focus(-1,1), vertex (-3,1).
 

LoveHateSchool

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no, your answer is correct for the vertex and focus you specified.

The answer they have given swaps the co-ordinates of the vertex and the focus. i.e. focus(-1,1), vertex (-3,1).
Aw thank you, I was really paranoid I was failing hardcore :)

ALso cause they somehow had it positive number for a concave left parabola.
 

gr_111

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Aw thank you, I was really paranoid I was failing hardcore :)

ALso cause they somehow had it positive number for a concave left parabola.
Yep, dw you're all over it! You should download "Geogebra", a free graphing program which makes it really easy to see whats happening with graphs and why a graph looks like it does.
 

Demise

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Find eqn of the parabola vetex (-1,1) and focus (-3, 1)

(y - 1)^2 = -8(x+1)

Just did the question and thought WTF how can I be wrong... Cheers for clearing it up gr_111.
 

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