જો સામાન્ય ગુણોત્તર \(r (r>1)\) વાળી એક ગુણોત્તર શ્રેણી (\(G.P.\)) ના ત્રણ ક્રમિક પદો , એ એક ત્રિકોણની ત્રણ બાજુઓની લંબાઈઓ છે અને \([\mathrm{r}]\) એ \(\mathrm{r}\) કે તેથી નાનો હોય તેવો મહત્તમ પૂર્ણાંક દર્શાવે છે, તો \(3[\mathrm{r}]+[-\mathrm{r}] =\) ...........

A \(1\)
B \(2\)
C \(3\)
D \(4\)

Verified Solution

Answer & Solution

Correct Answer

(A) \(1\)

Step-by-step Solution

Detailed explanation

\(\text { a, ar, } a r^2 \rightarrow \text { G.P. }\) Sum of any two sides \(>\) third side \( a+a r>a r^2, a+a r^2>a r, a r+a r^2>a \) \( r^2-r-1<0 \) \( r \in\left(\frac{1-\sqrt{5}}{2}, \frac{1+\sqrt{5}}{2}\right) \) \( r^2-r+1>0\) \(............(1)\) always true…

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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