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TS EAMCET · Maths · Properties of Triangles

If \(b+c=3 a\), then \(\cot \frac{B}{2} \cot \frac{C}{2}\) is equal to :

  1. A 3
  2. B 1
  3. C 4
  4. D 2
Verified Solution

Answer & Solution

Correct Answer

(D) 2

Step-by-step Solution

Detailed explanation

\(\cot \frac{B}{2} \cdot \cot \frac{C}{2}\) \(=\sqrt{\frac{s(s-b)}{(s-c)(s-a)}} \times \sqrt{\frac{s(s-c)}{(s-a)(s-b)}}\) \(=\frac{s}{s-a}=\frac{2 a}{2 a-a}=2 \quad(\because b+c=3 a)\)