y=sinxcosπ/6+cosxsinπ/6+sinxcosπ/6-cosxsinπ/6+cosx
=√3sinx+cosx
=2(sinx√3/2+cosx*1/2)
=2(sinxcosπ/6+cosxsinπ/6)
=2sin(x+π/6)
-π/3