Răspunsuri

2014-02-25T19:43:43+02:00
(sin x+cosx)²=sin²x+2 *sin x * cos x+ cos²x dar sin²x + cos ² x =11-2*sin ²x = sin ²x+cos²x-2*sin²x=cos²x-sin²x=cos²x-(1-cos²x)=2 cos²x -1