Jawabanmu

2014-05-02T11:37:41+07:00
1/x^2 - sin 2x/(2x^2 tanx) =
= 1/x^2 - 2 sin x cos x/ (2x^2 tan x)
= 1/x^2 - 2 sin x cos x / (2x^2 (sin x / cos x))
= 1/x^2 - 2 (cos x)^2/2x^2
= 1/x^2 - (cos x)^2/x^2
= ( 1 - (cos x)^2 ) / x^2
= (sin x)^2 / x^2
= 1