Published by:
CGP EDU Academic Team
Published on: August 12, 2026
If in a Δ ABC, a = 5, b = 4 and cos (A – B) = 
, then
A
c = 6
B
sin A = 
C
area of Δ ABC = 
D
c = 8
Text Solution
Verified by ExpertsThe correct answer is:
CHECK THE SOLUTION.
tan 
= 
cot 
.........(i)
tan 2 
= 
= 
= 
∴ tan 
= 
a = 5 and b = 4
∴ from equation (i), we get
= 
cot 
⇒ 
= 
cot 
⇒ cot 
= 
cos C = 
= 
= 
= 
cos C = 
⇒ c 2 = a 2 + b 2 – 2ab cos C ⇒ c = 6
, Area = 
ab sinC cosC = 
⇒ sinC = 
= 
Area = 
× 5 × 4 × 
Area = sq. unit. From Sine rule
= 
= 
⇒ sinA = 
= 
∴ sinA = 
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