化简cos(5/2π+α)

[sin(5π-α)cos(-π-α)]/[cos(α-π)cos(π/2+α)]化简 cos^2α+cos^2(α+π/3)-cosαcos(α+π/3)化简 化简cos(5/2π+α) 2sinα*cosα*cos(2π-α)+cos(π+2α)*cosα*tanα化简! cos(α+5π/12)cos(α+π/6)+cos(π/12-α)cos(π/3-α) 化简 化简:cosα+cos(2π/3-α)+cos(2π/3+α) 化简:cos(-π-α) 化简sin(α-5π)/cos(3π-α)×cos(π/2-α)/sin(α-3π)×cos(8π-α)/sin(-α-4π) 计算：cos（π/5)+cos（2π/5)+cos(3π/5)+cos(4π/5) 【2cos³α-cos²α+cosα-2】/2cos²α+cosα+2化简 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) 化简sin(π/2+α)cos(3π-α)tan(π+α)/cos(π/2-α)cos(-α-π) 化简{sin(π+α)^3cos(-α)cos(π+α)}/{tan(π+α)^3cos(-π-α)^2} 5cos^2a+4cos^2β=4cosα则cos^2a+cos^2β (1+sinα+cosα)*[sin(α/2)-cos(α/2)]/√(2+2cosα)化简 （3/2*π 化简[tan(2π-α)sin(-2π-α)cos(6π-α)]/[cos(α-π)sin(5π-α)]