Answer each of the following questions in one word or one sentence or as per exact requirement of for question:
In any triangle ABC, find the value of a sin(B−C)+b sin (C−A)+c sin (A−B.)
a sin(B−C)+b sin (C−A)+c sin (A−B.)=k sin A sin (B−C)+k sin B sin (C−A)+k sin C sin (A−B)=k sin (π−(B+C)) sin (B−C)+k sin (π−(C+A)) sin (C−A)+k sin (π−(A+B)) sin (A−B)=k sin (B+C) sin (B−C)+k sin (C+A) sin (C−A) + k sin (A+B) sin (A−B)=k[sin2 B−sin2 C+sin2 C−sin2 A+sin2 A−sin2 B]=k×0=0