If `cos(A+B) sin (C-D) = cos (A-B) sin (C+D)`, then show that `tan A tan B tan C + tan D =0`

If (" cos " (A+B))/(" cos " (A-B)) =(" sin " (C+D))/(" sin " (C -D)) , prove that tan A tan B tan C + tan D=0

If (cos (AB)) / (cos (A + B)) + (cos (C + D)) / (cos (CD)) = 0 Prove that tan A tan B tan C tan D = -1

(cos (AB)) / (cos (A + B)) + (cos (C + D)) / (cos (CD)) = 0rArr tan A tan B tan C tan D =

If (cos(A-B))/(cos(A+B))+(cos(C+D))/(cos(C-D))=0, prove tht tan A tan B tan C tan D=-1

If cos2B=(cos(A+C))/(cos(A-C)) , then tan A, tan B, tan C are in

If A+B+C=pi and cos A= cos B.cos C prove that tan A= tan B+ tan C

If cos A = tan B , cos B = tan C and cos C = tan A then show that sin A = sin B = sin C = 2sin 18^circ .