`sin (A+B+C)+sin(A-B-C)+sin(A+B-C)+sin(A-B+C)=`

19. Prove that sin(A +B) sin(A-B)+sin(B+C)sin(B-C) + sin(C+A) sin(C-A)=0

Simplify: sin (B + C) sin (B - C) + sin (C + A) sin (C - A) + sin(A + B) sin (A - B)

Simplify: sin (B + C) sin (B - C) + sin (C + A) sin (C - A) + sin(A + B) sin (A - B)

If A + B + C =180^@ , prove that : sin (B+C-A) + sin(C+ A-B)+ sin(A +B-C)=4sin A sinB sinC .

If p = sin (A-B) sin (C-D) q = sin (B-C) sin (A-D) , r = sin (C-A) sin (B- D) then

Show that 4 sin A sin Bsin C = sin(A+B-C) + sin (B+C-A) + sin(C+A-B)-sin(A+B+C).

Show that: sin A sin(B-C)+sin B sin(C-A)+sin C sin(A-B)=0

sin(B+C-A),sin(C+A-B),sin(A+B-C)sin(B+C-A),sin(C+A-B),sin(A+B-C) are A.P., then cot A,cot B,cot C are in GP(b)HP(c)AP(d) none of these

Prove that (sin (A - B))/( sin A sin B ) + ( sin (B -C))/( sin B sin C ) + (sin (C - A))/( sin C sin A) =0