Решите уравнение sin9xsin3x=1/2 cos6x

Question

Решите уравнение sin9xsin3x=1/2 cos6x

Answer 1

1/2(cos6x-cos12x)=1/2cos6x
1/2cos6x-1/2cos12x=1/2cos6x
-1/2cos12x=0
cos12x=0
12x=П/2+Пn
x=П/24+Пn/12