Question

решите уравнение sin9xcos2x - cos9xsin2x = - sqrt(3)/2

Answer 1

sin(9x-2x)=-√3/2
sin7x=-√3/2
7x=(-1)^(n+1)*π/3+πn
x=(-1)^(n+1)*π/21+πn/7,n∈z

Answer 2

sin(9x-2x)=√3/2   sin7x=√3/2    7x=(-1)ⁿπ/3+πk
x=(-1)ⁿπ/21+πk/7   k∈Z