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COMEDK · Maths · 13. Parabola

The parametric equation of a parabola is \(x=t^{2}+1, y=2 t+1\). The cartesian equation of its directrix is

  1. A \(y=0\)
  2. B \(x=-1\)
  3. C \(x=0\)
  4. D \(x-1=0\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(x=0\)

Step-by-step Solution

Detailed explanation

Given that, \(x=t^{2}+1 \Rightarrow x-1=t^{2}\) and \(\quad y=2 t+1 \Rightarrow y-1=2 t\) Now, \(\quad(y-1)^{2}=4 t^{2}=4(x-1)\) \((y-1)^{2}=4(x-1)\) So, \(x-1=-1\) \(\Rightarrow \quad x=0\)