Jawabanmu

2014-06-04T17:10:05+07:00
(Cos x + Sin x )²
= cos² x + 2 sin x cos x + sin² x

karena cos² x = 1 - sin² x maka =

cos² x + 2 sin x cos x + sin² x
=
1 - sin² x + 2 sin x cos x + sin² x
= 1 +
2 sin x cos x  . terbukti
2014-06-04T17:27:34+07:00
Ingat: cos²x + sin² x = 1

(cos x + sin x)² = cos²x + 2sin x cos x + sin²x = cos² x + sin²x + 2sin x cos x = 1 + 2 sin x cos x