In a triangle,prove that sin3Asin(B-C)+sin3Bsin(C-A)+sin3Csin(A-B)=0

Hint: Take the first term i.e. sin3Asin(B-C). Use the identity for 2sinAsinB. Do this for all the three terms given in the question. Then try to use the concept that A+B+C = pi. using it try to make the same angles which can be cancelled after that. Thanks.