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TS EAMCET · Maths · Parabola

If \(2 x+3 y+12=0\) and \(x-y+4 \lambda=0\) are conjugate with respect to the parabola \(y^2=8 x\), then \(\lambda\) is equal to

  1. A \(2\)
  2. B \(-2\)
  3. C \(3\)
  4. D \(-3\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(-3\)

Step-by-step Solution

Detailed explanation

Using the condition that if two lines \(l_1 x+m_1 y+n_1=0\) and \(l_2 x+m_2 y+n_2=0\) are conjugate w.r.t. parabola \(y^2=4 a x\), then \[ l_1 n_2+l_2 n_1=2 a m_1 m_2 \] Given conjugate lines are \(2 x+3 y+12=0\) and \(x-y+4 \lambda=0\) and equation of parabola is \(y^2=8 x\).…