求值:cos(π/11)cos(2π/11)cos(3π/11)cos(4π/11)cos(5π/11)

求值：cos（25π /4） 三角函数已知P(-4,3) 求(cos((π/2)+x)sin(-π-x))/(cos((11π/2)-x)sin((9 【紧急求助】计算:cosα+cos(2π/3 +α)+cos（4π/3 +α） 若cos（π/4+x)=3/5,求值 8sin(π/32)cos(π/32)cos(π/16)cos(π/8),求值 已知cos（π4 cos(π/32)*cos(π/16)*cos(π/8)= cos^2(π/3-a)+cos^2(π/6+a) cos(2π/3-α)能等于cosα? 求值：sin(π/12)+cos(π/12) 求值cos5π/8*cosπ8 cos(-2/3)π=?