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TS EAMCET · Maths · Circle

If the tangents \(x+y+k=0\) and \(x+a y+b=0\) drawn to the circle \(S \equiv x^2+y^2+2 x-2 y+1=0\) are perpendicular to each other and \(k, b\) are both greater than 1 , then \(b-k=\)

  1. A \(\sqrt{2}\)
  2. B 0
  3. C 2
  4. D \(2 \sqrt{2}\)
Verified Solution

Answer & Solution

Correct Answer

(C) 2

Step-by-step Solution

Detailed explanation

Slope of \(x+y+k=0\) is \(m_1=-1\) Slope of \(x+a y+b=0\) is \(m_2=-\frac{1}{a}\) \(m_1 m_2=-1 \Rightarrow-1 \times\left(\frac{-1}{a}\right)=-1 \Rightarrow a=-1\) Centre of circle is \((-1,1) \Rightarrow \frac{-1+1+k}{\sqrt{2}}=1 \Rightarrow k=\sqrt{2}\)…