Published by:
CGP EDU Academic Team
Published on: August 12, 2026
In a triangle ABC, if cosA + 2cos B + cos C = 2 then -
A
tan 
= 3
= 3
B
cot 
cot 
= 3
cot = 3
C
cot 
+ 
= 2cot 
+ = 2cot
D
a, b, c are in A.P.
Text Solution
Verified by ExpertsThe correct answer is:
CHECK THE SOLUTION.
(b, c, d)
cos A + 2 cos B + cos C = 2
⇒ cos A + cos C = 2 (1 – cos B) = 2 · 2 sin 2 
⇒ 2 cos 
cos 
= 4 sin 2 
⇒ 2 sin 
cos 
= 4 sin 2 
⇒ cos 
= 2 sin 
= 2 cos 
⇒ cos 
cos 
= 3 ∴ holds
Again cot 
+ cot 
+ cot 
= cot 
cot 
cot 
= 3 cot 
⇒ cot 
+ cot 
= 2 cot 
∴ holds Again cot 
+ cot 
= 3
⇒ 
= 3
⇒ 
= 3 ⇒ 2s = 3b
⇒ a + b + c = 3b ⇒ a + c = 2b
⇒ a, b, c are in A.P.
∴ holds
∴ , , hold
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