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TS EAMCET · Maths · Circle

The power of a point \((2,0)\) with respect to a circle \(S\) is -4 and the length of the tangent drawn from the point \((1,1)\) to \(S\) is 2 . If the circle \(S\) passes through the point \((-1,-1)\), then the radius of the circle \(S\) is

  1. A 2
  2. B \(\sqrt{13}\)
  3. C 3
  4. D \(\sqrt{10}\)
Verified Solution

Answer & Solution

Correct Answer

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

Step-by-step Solution

Detailed explanation

Let equation of circle be \(x^2+y^2+2 g x+2 f y+C=0\) Since \((-1,-1)\) lies on circle \(\therefore 1+1-2 g-2 f+C=0 \Rightarrow 2 g+2 f-C=2 \quad ...\mathrm{(i)}\) Since, power of a point \((2,0)\) with respect of circle…