Y=sin(x+6/π)+sin(x-6/π)+cosx
问题描述：
Y=sin(x+6/π)+sin(x-6/π)+cosx
答
Y=sin(x+6/π)+sin(x-6/π)+cosx
=sinxcosπ/6+cosxsinπ/6+sinxcosπ/6-cosxsinπ/6+cosx
=√3sinx+cosx
=2(√3/2*sinx+1/2*cosx)
=2sin(x+π/6)