Respostas

2013-11-05T14:51:01-02:00
Sen x - cos x = 1/2
(sen x - cos x)² = (1/2)²
sen²x - 2 sen x cos x + cos²x = 1/4
sen²x + cos²x - 2 senx cos x = 1/4
1 - 2 sen xcosx = 1/4
-2 senxcosx = 1/4 - 1
-2 senx cosx = -3/4
2 senx cosx = 3/4
sen x cos x = 3/4 . 1/2
sen x cos x = 3/8