sin(π/10)cos(π/5)

sin(π/10)cos(π/5) cos^2(π/5)+sin^2(π/10) 求值 cos 5π/8 cos π/8 + sin 5π/8 sin π/8= 若(4sinα-2cosα)/(5cosα+3sinα)=10,且α∈(-π/2,0)则cosα值为 利用和差角公式化简 (2)sin(π/3+α)+sin(π/3-α)(2)sin(π/3+α)+sin(π/3-α)(3)cos(π/4+α)-cos(π/4-α)(4)cos(60°+α)+cos(60°-α)(5)sin(α-β)cosβ+cos(α-β)sinβ(6)cos(α+β)cosβ+sin(α+β)sinβ sin(a-π)+5cos(2π-a)+4cos(π+a)/cos(π-a)-sin(-a) 求 [sin(5π-α)cos(-π-α)]/[cos(α-π)cos(π/2+α)]化简 已知sinα+cosα=4/5且3π/22,若sinα+sinβ+sinγ=0,cosα+cosβ+cosγ=0,则cos(α-β)的值 sin(α-β)sin(β-r)-cos(α-β)cos(r-β) 1.sin(α-β)sin(β-r)-cos(α-β)cos(r-β)2.（ tan4分之5π+tan12分之5π）/（1-tan12分之5π）3.[ sin（α+β）-2sinαcosβ]/2sinαsinβ+cos（α+β） 化简sin(α-5π)/cos(3π-α)×cos(π/2-α)/sin(α-3π)×cos(8π-α)/sin(-α-4π) 化简：[sin( π －a) cos( π+a)cos(3/2 π+a )]/cos(3 π-a )sin(3 π+a )sin(5/2 π-a ) 已知sin(3π+α)=2cos(α-4π)求cos(π/2 -α)+5sin(π/2 +α)/2cos(π+α)-sin(-α) 【三角函数】已知sin(α-π)=2cos(2π-α),求[sin(π-α）+5cos（2π-α)]/[3cos(π-α）-sin（-α)] 已知sin(a-π)=2cos(2π-a),求(sin(π-a)+5cos(2π-a))/(3cos(π-a)-sin(-a))的值. sin(a-π)=2cos(2π-a).求3cos(π-a)-sin(-a)/sin(π-a)+5cos(2π-a) 若sin(π-a)=2cos(2π-a),求sin(π-a)+5cos(2π-a)/3cos(π-a)-sin(-a)的值 已知sin(a-π)=2cos(2π-a),求sin(π-a)+5cos(2π-a)/3cos(π-a)+sin(-a)的值. sin(π-θ）+cos(2π-θ）/cos(5π/2-θ)+sin(3π/2+θ)=2,则sinθcosθ=______