cos(π/11)cos(2π/11)cos(3π/11)cos(4π/11)cos(5π/11)怎么解

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cos(π/11)cos(2π/11)cos(3π/11)cos(4π/11)cos(5π/11)怎么解cos(π/11)cos(2π/11)cos(3π/11)cos(4π/11)cos(5π/11

cos(π/11)cos(2π/11)cos(3π/11)cos(4π/11)cos(5π/11)怎么解
cos(π/11)cos(2π/11)cos(3π/11)cos(4π/11)cos(5π/11)怎么解

cos(π/11)cos(2π/11)cos(3π/11)cos(4π/11)cos(5π/11)怎么解
cos(π/11)cos(2π/11)cos(3π/11)cos(4π/11)cos(5π/11)
=2sin(π/11)cos(π/11)cos(2π/11)cos(3π/11)cos(4π/11)cos(5π/11)/[2sin(π/11)]
=2sin(2π/11)cos(2π/11)cos(3π/11)cos(4π/11)cos(5π/11)/[4sin(π/11)]
=2sin(4π/11)cos(4π/11)cos(3π/11)cos(5π/11)/[8sin(π/11)]
=sin(8π/11)cos(3π/11)cos(5π/11)/[8sin(π/11)]
=2sin(3π/11)cos(3π/11)cos(5π/11)/[16sin(π/11)]
=sin(6π/11)cos(5π/11)/[16sin(π/11)]
=2sin(5π/11)cos(5π/11)/[32sin(π/11)]
=sin(10π/11)/[32sin(π/11)]
=sin(1π/11)/[32sin(π/11)]
=1/32

cos(π/11)cos(2π/11)cos(3π/11)cos(4π/11)cos(5π/11)怎么解 求值:cos(π/11)cos(2π/11)cos(3π/11)cos(4π/11)cos(5π/11) 求值:cos(π/11)-cos(2π/11)+cos(3π/11)-cos(4π/11)+cos(5π/11) cos(π/11)cos(2π/11)cos(3π/11)cos(4π/11)cos(5π/11) 利用诱导公式求三角函数值 cos 6/65π一,利用诱导公式:cos(2kπ+α)=cosα (k∈Z)和cos(π-α)=-cosα 得出cos65π/6=cos(65π/6-10π)=cos(5π/6)=cos(π-π/6)=-cosπ/6=-√3/2二,又或者cos65π/6=cos(11π-1π/6)=-cos( cos^2(π/6) 根号(1-cosθ/1+cosθ)+根号(1+cosθ/1-cosθ)θ属于(π/2,π) 【紧急求助】计算:cosα+cos(2π/3 +α)+cos(4π/3 +α) 化简:[sin(2π-a)cos(π+a)cos(π/2+a)cos(11π/2-a)[sin(2π-a)cos(π+a)cos(π/2+a)cos(11π/2-a)]/[cos(π-a)sin(3π-a)sin(-π-a)sin(9π/2+a)] 在△ABC中,根号3cos(B+C)求根号3cos(B+C)+COS(π/2+A)的取值范围 三角函数计算cosα=1/7,cos(α+β)=-11/14,α、β∈(0,π/2),求cosβ 已知cosα=1/7,cos(α+β)=-11/14,且α、β∈(0,2/Π),求cosβ的值 已知COSα=1/7,COS(α+β)=-11/14,且α,β属于0到2/π,求COSβ 利用公式C(α-β)证明cos(π/2-a)=sin α.cos(2π-α)=cos α 利用公式C (α-β)证明:(1) cos (π/2-α)=sin α; (2) cos (2π-α)=cos α. 化简[sin(2π-α)cos(π+α)cos(π/2+α)cos(11π/2-α)]/[cos(π-α)sin(π+α)sin(-π-α)sin[(...化简[sin(2π-α)cos(π+α)cos(π/2+α)cos(11π/2-α)]/[cos(π-α)sin(π+α)sin(-π-α)sin[(9π/2)+α]] 求cos(π/11)cos(2π/11)cos(3π/11)cos(4π/11)cos(5π/11)求值:cos(π/11)cos(2π/11)cos(3π/11)cos(4π/11)cos(5π/11)(5/24)(11/24)=5/11?,而且过程和题好像都没关系。 求证,cos(A/2)+cos(B/2)+cos(C/2)=4cos((π-A)/4)*cos((π-B)/4)*cos((π-C)/4)A+B+C=180度.谢谢高一的