જેની પ્રધાનઅક્ષ \(x -\) અક્ષ અને કેન્દ્ર ઉંગમબિંદુ હોય તેવા ઉપવલયના નાભીલંબની લંબાઈ \(8\) છે જો બંને નાભીઓ વચ્ચેનું અંતર તેની ગૌણઅક્ષની લંબાઈ જેટલું હોય તો નીચેનામાંથી ક્યું બિંદુ ઉપવલય પર આવેલ નથી ?

A \(\left( {4,\sqrt 2 ,2\sqrt 2 } \right)\)
B \(\left( {4,\sqrt 3 ,2\sqrt 2 } \right)\)
C \(\left( {4,\sqrt 3 ,2\sqrt 3 } \right)\)
D \(\left( {4,\sqrt 2 ,2\sqrt 3 } \right)\)

Verified Solution

Answer & Solution

Correct Answer

(B) \(\left( {4,\sqrt 3 ,2\sqrt 2 } \right)\)

Step-by-step Solution

Detailed explanation

Consider \(\frac{{{x^2}}}{{{a^2}}} + \frac{{{y^2}}}{{{b^2}}} = 1\) Given that \(2b = 2ae\) \( \Rightarrow b = ae\) and \(\frac{{2{b^2}}}{a} = 8\) \(a\left( {1 - {e^2}} \right) = 4,{a^2}{e^2} = {a^2}\left( {1 - {e^2}} \right)\) \( \Rightarrow {e^2} = \frac{1}{2}\)…

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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