Question

Срочно
Cos30° cos15° - sin30° sin15°

Answer 1

cos(α)*cos(β)-sin(α)*sin(β)=cos(α+β), cos(30°)*cos(15°)-sin(30°)*sin(15°)=cos(30°+15°)=cos(45°)=√2/2. Ответ: √2/2.