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If the equation of the parabola is x2 = – 8y, find coordinates of the focus, the equation of the directrix and length of latus rectum. - Mathematics

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Question

If the equation of the parabola is x2 = – 8y, find coordinates of the focus, the equation of the directrix and length of latus rectum.

Sum
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Solution

The given equation is of the form x2 = – 4ay where a is positive

Therefore, the focus is on y-axis in the negative direction and parabola opens downwards.

Comparing the given equation with standard form, we get a = 2.

Therefore, the coordinates of the focus are (0, –2)

And the the equation of directrix is y = 2

And the length of the latus rectum is 4a, i.e., 8.

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Chapter 11: Conic Sections - Solved Examples [Page 193]

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NCERT Exemplar Mathematics [English] Class 11
Chapter 11 Conic Sections
Solved Examples | Q 2 | Page 193

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