化简数学函数化简[(cos²(π/2+α)-sin²(7π/2+α))/(sinα+cosα)]-sin(7π-α)化简这道数学题,

化简数学函数化简[(cos²(π/2+α)-sin²(7π/2+α))/(sinα+cosα)]-sin(7π-α)化简这道数学题,
化简数学函数
化简[(cos²(π/2+α)-sin²(7π/2+α))/(sinα+cosα)]-sin(7π-α)化简这道数学题,

化简数学函数化简[(cos²(π/2+α)-sin²(7π/2+α))/(sinα+cosα)]-sin(7π-α)化简这道数学题,

原式=（sin²α-cos²α）/（sinα+cosα）-sin（π-α）
=sinα-cosα-sinα
=-cosα

[(cos²(π/2+α)-sin²(7π/2+α))/(sinα+cosα)]-sin(7π-α)
=（sin²α - cos²α)/(sinα+cosα） - sin（π-α)
=sinα - cosα - sinα
=-cosα