Show that the expression (a\sin(B-C) + b\sin(C-A) + c\sin(A-B)) equals 0

In any triangle ABC,

a/sin A = b/sin B = c/sin C = k

a = k sin A, b = k sin B, c = k sin C

LHS

= a sin (B C) + b sin (C A) + c sin (A B)

= k sin A [sin B cos C cos B sin C] + k sin B [sin C cos A cos C sin A] + k sin C [sin A cos B cos A sin B]

= k sin A sin B cos C k sin A cos B sin C + k sin B sin C cos A k sin B cos C sin A + k sin C sin A cos B k sin C cos A sin B

= 0

= RHS

Hence proved that a sin (B C) + b sin (C A) + c sin (A B) = 0.

      The proof provided attempts to show that the expression (a\sin(B-C) + b\sin(C-A) + c\sin(A-B)) equals 0 in any triangle ABC. However, there seems to be a mistake in the algebraic manipulation of the trigonometric identities, leading to the incorrect conclusion that the left-hand side (LHS) is equal to the right-hand side (RHS). To ensure the correctness of the proof, it is crucial to carefully verify each step of the trigonometric calculations and identities used in the derivation. Additionally, presenting a clear and logical progression of the proof with proper explanation of each step can enhance the understanding and validity of the mathematical argument. If you need further clarification or assistance in revising the proof, please feel free to reach out.    

Sample Answer