[" 20.If "(cos(A-B))/(cos(A+B))+(cos(C+D))/(cos(C-D))=0," prove that "],[tan A.tan B.tan C.tan D=-1]

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 (cos(A-B))/("cos"(A+B))+("cos"(C+D))/("cos"(C-D))=0,\ prove tht tanAtanBtanCtanD=-1

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

(cos(A-B))/(cos(A+B))+cos(C+D)/(cos(C-D))=0 => tan A tan B tan C tan D =

(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)) =( sin (C+D))/( sin (C -D)) then prove that tan A tan B tan C + tan D=0 ................. A) 0 B) -1 C) sqrt3 D) 1

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

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