sin^4α-cos^4α
=(sin²α+cos²α)(sin²α-cos²α)
=-cos(2α)
=2sin²α-1
=2•(√5/5)²-1
=-3/5
sina=根号5／5则sin^4a-cos^4a=
1个回答
相关问题
-
已知sina=根号5/5,则sin^4-cos^4a得值?
-
已知sina=根号5/5,则sin^4a-cos^4a的值为_____,
-
sin(a+π/3)+sina= - 4根号3/5,则cos(a+2π/3)
-
已知cos(a+兀/6)-sina=4/5根号3,则sin(a-兀/6)=
-
已知cos(a-π/6）+sina=4根号下3/5,则sin(a+7π/6)=?
-
COS(A-30度)+SINA=4/5 乘根号3 求SIN(A+210度)?
-
已知cos（a+pai/6）—sina=4/5根号3,则sin（a—pai/6）的值是?
-
若cos(a+B)*cosa+sin(a+B)*sina=-4/5,则sin(π/2-B)
-
若sina+cosa/sina-cosa=2,则4sin^2a-3sinacosa-5cos^2a=
-
已知cos(a-派/6)+sina=4/5根号3,则sin(a+7/6派)的值是?