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) sin (C- D) = cos (A- B) sin (C+D) , show that : tan A tan B tanC + tanD=0 .

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

If A + B + C = pi " and " cos A = cos B cos C, "show that" tan A = tan B + tan C

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

If cos 2 A sin 2 B= cos 2 C sin 2D , prove that tan (C+A) tan (C-A) tan (B+D)= tan (D-B)

If A + B + C= pi and cos A = cos B cos C, show that tan A =tan B + tan C and cot B cot C=1/2.