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CLASS_11_MATHS_SOLUTIONS_NCERT

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Class XI Chapter <strong>11</strong> – Conic Section Maths<br />

______________________________________________________________________________<br />

Let AB intersect the x-axis at point C.<br />

Let OC = k<br />

From the equation of the given parabola, we have<br />

2<br />

y 4ak y 2 ak<br />

∴The respective coordinates of points A and B are k,2 ak ,and k,-2 ak <br />

AB = CA + CB = 2 ak + 2 ak = 4 ak<br />

Since OAB is an equilateral triangle, OA 2 = AB 2 .<br />

2 4<br />

<br />

2 2<br />

2<br />

k ak ak<br />

<br />

<br />

2<br />

k<br />

12ak<br />

k<br />

12a<br />

2<br />

k 4ak 16ak<br />

2<br />

AB 4 ak 4 a12a 4 12a 8 3a<br />

Thus, the side of the equilateral triangle inscribed in parabola y 2 = 4 ax is 8 3a<br />

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