Jawabanmu

2014-05-24T09:48:50+07:00
2 tan x / 1 + tan² x
= 2 tan x / 1 + sec² x - 1
= 2 (sin x / cos x) / (1/cos² x)
= 2 sin x . cos² x / cos x
= 2 sin x . cos x
= sin 2x