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CGP EDU Academic Team
Published on: August 12, 2026
In Δ ABC, bc = 2b 2 cosA + 2c 2 cosA – 4bc cos 2 A, then Δ ABC is
Text Solution
Verified by ExpertsThe correct answer is:
A
bc = 2b 2 cosA + 2c 2 cosA – 4bc cos 2 A
⇒ bc =2 cosA (b 2 + c 2 – 2bc cosA)
⇒ bc = (2cosA)a 2
⇒ 
= cosA = 
⇒ b 2 c 2 = a 2 (b 2 + c 2 – a 2 )
⇒ (a 2 –b 2 ) (a 2 – c 2 ) = 0
Thus, triangle is isosceles
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