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COMEDK · Maths · 12. Circle

If the circles \(x^{2}+y^{2}-2 x-2 y-7=0\) and \(x^{2}+y^{2}+4 x+2 y+k=0\) cut orthogonally, then the length of the common chord of the circles is

  1. A 2
  2. B \(12 / \sqrt{13}\)
  3. C 8
  4. D 5
Verified Solution

Answer & Solution

Correct Answer

(B) \(12 / \sqrt{13}\)

Step-by-step Solution

Detailed explanation

We have, \[ \begin{aligned} &S_{1}: x^{2}+y^{2}-2 x-2 y-7=0 \\ &S_{2}: x^{2}+y^{2}+4 x+2 y+k=0 \end{aligned} \] Since, \(S_{1}\) and \(S_{2}\) cut orthogonally, then…