cos^2(π/6)
cos^2(π/6)
cos^2(π/3-a)+cos^2(π/6+a)
计算cos(a+5π/12)cos(a+π/6)+cos(π/12-a)cos(π/3-a)
【紧急求助】计算:cosα+cos(2π/3 +α)+cos(4π/3 +α)
求证:[tan(2π-α)cos(3π/2-α)cos(6π-α)]/[sin(α+3π/2)cos(α+3π/2)]=
求证:[tan(2π-α)cos(3π/2-α)cos(6π-α)]/[sin(α+3π/2)cos(α+3π/2)]
已知f(x)=-1/2+sin(π/6-2x)+cos(2x-π/3)+cos平方x.
sin^2(α)+cosαcos(π/3+α)-sin^2(π/6-α)为定值,要证明
cos2A-cos2B=2cos(π/A)cos(π/6+A)知道的速度回答啊
求证sin^2α+cosαcos(π/3+α)-sin^(π/6-α)的值与α无关
化简sin(2π+a)cos(π-a)cos(π/2-a)cos(7π/2-a)/cos(π-a)sin(3π-a)si
cos(-π/2+a) 等于什么