The parametric equations of a parabola are x = t2 + 1, y = 2t + 1. The Cartesian equation of its directrix is
Given the parametric equations of a parabola x = t2 + 1 and y = 2t + 1.
Consider ,
⇒
⇒
⇒
⇒ (y - 1)2 = 4(x - 1)
Comparing with the standard form of parabola (y - a)2 = 4b(x - c) we get,
⇒ 4b = 4
⇒ b = 1
⇒ The equation of the directrix is x - c = - b
⇒ Directrix is x - 1 = - 1
⇒ Directrix is x = 1 - 1
⇒ Directrix is x = 0
∴The correct option is A