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AP EAMCET · Maths · Parabola

The angle subtended by the normal chord at the point \((9,9)\) on the parabola \(y^2=9 x\), at the focus of the parabola is

  1. A \(45^{\circ}\)
  2. B \(60^{\circ}\)
  3. C \(90^{\circ}\)
  4. D \(135^{\circ}\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(90^{\circ}\)

Step-by-step Solution

Detailed explanation

Parabola: \(y^2 = 9x \Rightarrow 4a = 9 \Rightarrow a = \frac{9}{4}\). Focus \(F = (a,0) = \left(\frac{9}{4}, 0\right)\). Point \(P = (9,9)\). For \(P=(at^2, 2at)\), \(2at = 9 \Rightarrow 2\left(\frac{9}{4}\right)t = 9 \Rightarrow \frac{9}{2}t = 9 \Rightarrow t = 2\). For a…