ExamBro
ExamBro
AP EAMCET · Maths · Properties of Triangles

In a triangle, if \(b=5, c=6, \tan \frac{A}{2}=\frac{1}{\sqrt{2}}\), then \(a=\)

  1. A \(\sqrt{41}\)
  2. B \(\sqrt{21}\)
  3. C \(\sqrt{14}\)
  4. D \(8 \sqrt{6}\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(\sqrt{41}\)

Step-by-step Solution

Detailed explanation

\(\because \cos A=\frac{1-\tan ^2 \frac{A}{2}}{1+\tan ^2 \frac{A}{2}}\) \(=\frac{1-\left(\frac{1}{\sqrt{2}}\right)^2}{1+\left(\frac{1}{\sqrt{2}}\right)^2}=\frac{1}{3}\) \(\cos A=\frac{b^2+c^2-a^2}{2 b c}\) \(\frac{1}{3}=\frac{(5)^2+(6)^2-a^2}{2(5)(6)}\)…