#4 sin x tan x - cos x cot x = 0# #4 sin x sin x/cos x - cos x cos x/sin x = 0# #4 sin^2 x/cos x - cos^2 x/sin x = 0# #4 sin^2 x/cos x=cos^2 x/sin x# #4 sin^3 x = cos^3 x# #4 tan^3 x = 1# #tan^3 x = 1/4# #tan x = root(3)(1/4)# #x = arctan root(3)(1/4)#