已知sinα＝√5／5,则sinα四次方－cosα四次方的值为

网友回答

sin^4α－cos^4α
=(sin²α+cos²α)(sin²α-cos²α)
=sin²α-cos²α
=sin²α-(1-sin²α)
=2sin²α-1
=-3/5======以下答案可供参考======
供参考答案1:
17/25