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 .