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AP EAMCET · Maths · Circle

If \(x+y-1=0\) and \(2 x-y+1=0\) are conjugate lines with respect to a circle \(x^2+y^2-4 x+2 f y-1=0\), then \(f=\)

  1. A -1 or 3
  2. B 1 or 2
  3. C -2 or 0
  4. D -1 or 2
Verified Solution

Answer & Solution

Correct Answer

(C) -2 or 0

Step-by-step Solution

Detailed explanation

Conjugate lines are : \(x+y-1=0,2 x-y+1=0\) \(\mathrm{l}_1=1, \mathrm{~m}_1=1, \mathrm{n}_1=-1, \mathrm{l}_2=2, \mathrm{~m}_2=-1, \mathrm{n}_2=1\) \(\begin{aligned} & \therefore \quad g=-2, c=-1 \\ & \text { Radius, } R=\sqrt{f^2+4+1}=\sqrt{f^2+5}\end{aligned}\) Now, the…
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