【已知cos(π/6-θ)=a(|a|】
更新时间：2026-10-01 17:01:29
问题描述:
已知cos(π/6-θ)=a(|a|
刘军胜回答:
cos(π/6-θ)=a cos(5π/6+θ) =-cos(π-5π/6-θ) =-cos(π/6-θ) =-a sin(2π/3-θ) =sin(π-2π/3+θ) =sin(π/3+θ) =cos(π/2-π/3-θ) =cos(π/6-θ) =a
已知cos(π/6-θ)=a(|a|
cos(π/6-θ)=a cos(5π/6+θ) =-cos(π-5π/6-θ) =-cos(π/6-θ) =-a sin(2π/3-θ) =sin(π-2π/3+θ) =sin(π/3+θ) =cos(π/2-π/3-θ) =cos(π/6-θ) =a