In the parabola y2 = 4ax, the length of the chord passing through the vertex and inclined to the axis at 
is
Given that we need to find the length of the chord of the parabola y2 = 4ax which passes through the vertex and is inclines to axis at 
.
We know that the vertex and axis of the parabola y2 = 4ax is (0, 0) and y = 0(x - axis).
We know that the equation of the straight line passing through the origin and inclines to the x - axis at an angle θ is y = tanθx.
⇒ 
⇒ y = 1.x
⇒ y = x.
The equation of the chord is y = x.
Substituting y = x in the equation of parabola.
⇒ x2 = 4ax
⇒ x = 4a.
⇒ y = x = 4a
The chord passes through the points (0, 0) and (4a, 4a).
We know that the distance between the two points (x1, y1) and (x2, y2) is 
.
⇒ 
⇒ 
⇒ 
⇒ l = 4√2 a
∴The correct option is A