Buktikan bahwa: tan x = (1 - cos 2x) / sin 2x

=> tanx
=> sinx/cosx
=> sinx × sinx × 2 / cosx × sinx × 2
=> 2sin^2x / 2sinx cosx
=> (1 - cos2x)/sin2x terbukti

Bab Trigonometri
Matematika SMA Kelas X

tan x = ((sin x)/(cos x))
tan x = ((sin x)/(cos x)) . (2 . sin x)/(2 . sin x)
tan x = (2 . sin² x) / (2 . sin x . cos x)
tan x = (1 - cos 2x) / (sin 2x)

◎
cos 2x = 1 - 2 sin² x
2 sin² x = 1 - cos 2x
◎