Published by:
CGP EDU Academic Team
Published on: August 12, 2026
In a triangle ABC, prove that for any angle θ , b cos (A − θ ) + a cos (B + θ ) = c cos θ .
Text Solution
Verified by ExpertsThe correct answer is:
CHECK THE SOLUTION.
L.H.S. {k = b(cos A cos θ + sin A sin θ ) + a(cos B cos θ – sin B sin θ )
= cos θ (b cos A + a cos B) + sin θ (b sin A – a sin B)
= c cos θ + 0 { b sin A – a sin B = 0}
= c cos θ = R.H.S.
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