Cos5x = cos7xsin3x - sin 2 x = (корень из 3) sin 7x

Question

Cos5x = cos7x
sin3x - sin 2 x = (корень из 3) sin 7x

Answer 1

Cos5x=cos7x
cos5x-cos7x=0
-2sin(5x+7x/2)cos(5x-7x/2)=0
-2sin6xcosx=0
sin6x=0. cosx=0
6x=πn. x=π/2+π n
x=π/6 n
n€Z