Jawabanmu

2014-04-12T18:05:16+07:00
Ingat rumus trigonometri (sudut rangkap) 
cos 2x = 1 - 2 sin^2 (x) atau : 1 - cos 2x = 2 sin^2 (x) 
=====================>1 - cos 4x = 2 sin^2 (2x) 
=====================>1 - cos 6x = 2 sin^2 (3x) , ...dan seterusnya :D