Tan 2x = ±√3 , jika sin² x = 1/4

sin² x = 1/4
sin x = ±(1/2)
maka
cos x = ±(√3 / 2)
tan x = ±(1/√3)

tan 2x = (2.tanx)/(1 - tan²x)
tan 2x = (2. ±(1/√3)) / (3/3 - 1/3)
tan 2x = ±(2/√3) / (2/3)
tan 2x = ±(3/√3)
           = ±√3