化简 co s 2 ( π 4 -α)-si n

化简 co s 2 ( π 4 -α)-si n 2 ( π 4 -α) 得到（　　） A．-cos2α B．-sin2

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化简：（1）cos(α+π)sin(−α)cos(−3π−α)sin(−α−4π)（2）cos(α−π2)sin(5π2
化简：[1+2sin(α+2π)*cos(α-2π)]/[sin(α+4π)+cos(α+8π)]
化简[sin(π/2+α)*cos(π/2-α)]/cos(π+α)+[sin(π-α)*cos(π/2+α)]/sin
化简[sin(π/2-α）cos(π/2-α)]/cos(π+α)-[sin(π-α)cos(π/2-α)]/sin(π
化简：2cos²α-1/【2sin(π/4-α)sin²(π/4+α)】
化简cos2(π/4-α)-sin2(π/4-α)
化简sin2α-2cos²α/sin（α-π/4）
化简cos(π-α)sin(α+2π)/cos^2(-α-π)tan(2π-α
化简cos(π+α)cos(π2+α)cos(11π2−α)cos(π−α)sin(−π−α)sin(9π2+α)的结果
（1）化简：sin(2π−α)cos(π+α)cos(3π2+α)cos(13π2−α)cos(π−α)sin(3π−α