∵Θ=5π/3∴x=5cosΘ=5cos5π/3=5cos(2π-π/3)=5cosπ/3=5/2y=5sinΘ=5sin5π/3=5sin(2π-π/3)=-5sinπ/3=-5根号3/2∴点P（5/2，-5根号3/2）
