Find the vertex, focus and directrix of the parabola 4y=x^2-2x+5
Thanks for answering!!! and can you shown as much as the working to me please???
Urgently ask parabola question
2009-05-24 4:03 am
回答 (1)
2009-05-24 4:39 am
✔ 最佳答案
For a parabola with axis parallel to the y-axis:
(x - h)2 = 4p(y - k)
Vertex = (h, k)
Focus = (h, k + p)
Directrix: y = k - p
4y = x2 - 2x + 5
x2 - 2x + 1 = 4y - 4
(x - 1)2 = 4(y - 1)
Hence, h = 1, p = 1, k = 1
Vertex = (1, 1)
Focus = (1, 1 + 1) = (1, 2)
Directrix: y = 1 - 1 and thus y = 0
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https://hk.answers.yahoo.com/question/index?qid=20090523000051KK01716