f(θ)=2cos＾3 θ+sin＾(2π-θ)+sin(π/2+θ）-3 / 2+2cos＾(π+θ)+cos(-θ),
f(π/6)=3√3/4+1/4+√3/2-3/2+3/2+√3/2
=(5√3+1)/4