Преобразуйте произведение в сумму sin (x+3.14/4)×sin (x-3.14/6)

Question

Преобразуйте произведение в сумму sin (x+3.14/4)×sin (x-3.14/6)

Answer 1

Решение
sin(x + (3,14/4))*sin(x - (3,14/6)) =(1/2)*(cos(x + (3,14/4)) - cos(x - (3,14/6)) =
 
(1/2)*(cos(x + (3,14/4)) + (-1/2)(cos(x - (3,14/6))