设f( θ)=2cos^3θ + sin^2 (2π-θ)+cos(-θ)-3 / 2+2cos^2(π+θ) + cos(2π-θ),则 f(π/3) =

设f( θ)=2cos^3θ + sin^2 (2π-θ)+cos(-θ)-3 / 2+2cos^2(π+θ) + cos(2π-θ),则 f(π/3) =
设f( θ)=2cos^3θ + sin^2 (2π-θ)+cos(-θ)-3 / 2+2cos^2(π+θ) + cos(2π-θ),则 f(π/3) =

设f( θ)=2cos^3θ + sin^2 (2π-θ)+cos(-θ)-3 / 2+2cos^2(π+θ) + cos(2π-θ),则 f(π/3) =
f( θ)=2cos^3θ + sin^2 (2π-θ)+cos(-θ)-3 / 2+2cos^2(π+θ) + cos(2π-θ)
=2cos^3θ + sin^2 θ+cosθ-3 / 2+2cos^2θ + cosθ
=2cos^3θ+ cos^2θ +2cosθ+(sin^2 θ+cos^2θ )-3/ 2
=2cos^3θ+ cos^2θ +2cosθ-1/ 2
∵cosπ/3=1/2
f(π/3) =2(1/2)^3+ (1/2)^2 +2(1/2)-1/ 2
=1/4+1/4+1-1/2
=1