TS EAMCET · Maths · Determinants
If \(a , b , c\) are the sides of a triangle ABC and then \(2(\cos A+\cos B +\cos C )=\) \(\left|\begin{array}{lll}b & 1 & a \\ a & 1 & c \\ c & 1 & b\end{array}\right|=0\),
- A 1
- B 2
- C 3
- D 4
Answer & Solution
Correct Answer
(C) 3
Step-by-step Solution
Detailed explanation
Given \(\left|\begin{array}{lll}\mathrm{b} & 1 & \mathrm{a} \\ \mathrm{a} & 1 & \mathrm{c} \\ \mathrm{c} & 1 & \mathrm{~b}\end{array}\right|=0\) b expand w.r.t ' \(\mathrm{R}_1\),…
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