cosx/4*sinп/5-sinx/4*cosп/5=-√2/2 помогите решить уравнение

cosx/4*sinπ/5-sinx/4-cosπ/5=-√2/2cosasinb-sinacosb=sin(b-a)sin(π/5-x/4)=-√2/2sin(x/4-π/5)=√2/2x/4-π/5=(-1)^n*π/4+πnx/4=π/5+(-1)^n*π/4+πnx=4π/5+(-1)^n*π+4πn