" Life is not a problem to be solved but a reality to be experienced! "
© Copyright 2013 - 2025 KUDO.TIPS - All rights reserved.
ingat identitas trigonometri : cos²x - sin²x = cos 2x
(cosx+sinx)(cosx-sinx) = cos 2x
jadi (cosx-sinx) = (cos 2x)per √2 cosx