Question

(cos 15°+ sin 15°)²​

Answer 1

Ответ:

(cos15+sin15)² = cos²15 + 2* cos15 * sin15 + sin²15 = 1 + sin2*15 = 1 + sin30 = 1+ 1/2 = 1 1/2

P. S.  cos²a + sin²a=1

        2*sina * cosa = sin2a