मराठी

An equilateral triangle is inscribed in the parabola y2 = 4ax whose one vertex is at the vertex of the parabola. Find the length of the side of the triangle. - Mathematics

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प्रश्न

An equilateral triangle is inscribed in the parabola y2 = 4ax whose one vertex is at the vertex of the parabola. Find the length of the side of the triangle.

बेरीज
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उत्तर

As shown in the figure APQ denotes the equilateral triangle with its equal sides of length l (say).


Here AP = l

So AR = l cos30°

= `l  sqrt(3)/2`

Also, PR = `l  sin 30^circ = l/2`.

Thus `(lsqrt(3))/2, l/2` are the coordinates of the point P lying on the parabola y2 = 4ax.

Therefore, `l^2/4 = 4a  (lsqrt(3))/2`

⇒ `l = 8 asqrt(3)`.

THus, 8 `asqrt(3)` is the required length of the side of the equilateral triangle inscribed in the parabola y2 = 4ax.

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पाठ 11: Conic Sections - Solved Examples [पृष्ठ १९५]

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एनसीईआरटी एक्झांप्लर Mathematics [English] Class 11
पाठ 11 Conic Sections
Solved Examples | Q 8 | पृष्ठ १९५

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