cos(α+5π/12)cos(α+π/6)+cos(π/12-α)cos(π/3-α) 化简

cos(α+5π/12)cos(α+π/6)+cos(π/12-α)cos(π/3-α) 化简 [sin(5π-α)cos(-π-α)]/[cos(α-π)cos(π/2+α)]化简 化简:cos(-π-α) cos^3(-π-α) cos^2α+cos^2(α+π/3)-cosαcos(α+π/3)化简 化简cos(π/12-α)-根号3cos(5π/12+α) Cos(α-π) Cos(α- π/2 )如何化简 cos（π-α）=-cosα的推导过程 化简cos(5/2π+α) 化简cos（π/12）*cos（5π/12） cos (π/12) × cos(5×π/12)的值 cos(π/12)cos(5π/12)= cos(3π-α)=? 2sinα*cosα*cos(2π-α)+cos(π+2α)*cosα*tanα化简! 已知cos(5π/12-α)=m(lml≤1),求cos(π/12+α)和cos(11π/12-α)的值 已知cos(α+β)=12/13,cos(2α+β)=3/5,α∈(0,π/2),求cosα的值. 为什么cos（-α-π） = cos（α+π）还有-cos(-π-α)等于多少? 计算cos(a+5π/12)cos(a+π/6)+cos(π/12-a)cos(π/3-a）