माना सबसे बड़े तथा सबसे छोटे वत्तों, जो बिन्दु \((-4,1)\) से होकर जाते हैं तथा जिनके केन्द्र, वत्त \(x^{2}+y^{2}+2 x+4 y-4=0\) की परिधि पर स्थित हैं, की त्रिज्याएँ क्रमशः \(I _{1}\) तथा \(I _{2}\) हैं। यदि \(\frac{I_{1}}{I_{2}}=a+b \sqrt{2}\) है, तो \(a+b\) बराबर है

A \(3\)
B \(11\)
C \(5\)
D \(7\)

Verified Solution

Answer & Solution

Correct Answer

(C) \(5\)

Step-by-step Solution

Detailed explanation

Centre of smallest circle is \(\mathrm{A}\) Centre of largest circle is \(\mathrm{B}\) \(r_{2}=|C P-C A|=3 \sqrt{2}-3\) \(r_{1}=C P+C B=3 \sqrt{2}+3\) \(\frac{r_{1}}{r_{2}}=\frac{(3 \sqrt{2}+3)^{2}}{9}=(\sqrt{2}+1)^{2}=3+2 \sqrt{2}\) \(a=3, b=2\)

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

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\(x_i\)	\(0\)	\(1\)	\(5\)	\(6\)	\(10\)	\(12\)	\(17\)
\(f_i\)	\(3\)	\(2\)	\(3\)	\(2\)	\(6\)	\(3\)	\(3\)