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

Let OAB be the equilateral triangle inscribed in parabola y2 = 4ax.

Let AB intersect the x – axis at point C.



Let OC = k


From the equation of the given parabola, we have,


y2 = 4ak


y = 2


Thus, the respective coordinates of points A and B are (k, 2 ), and (k, -2)


AB = CA + CB = 2


Since, OAB is an equilateral triangle, OA2 = AB2.


Thus,


k2 + 4ak = 16ak


k2 = 12ak


k = 12a


Thus, AB =


Thus, the side of the equilateral triangle inscribed in parabola y2 = 4ax is .


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