已知cos(2a-b)=-11/14,sin(a-2b)=4√3/7,0
已知cos(2a-b)=-11/14,sin(a-2b)=4√3/7,0
已知cos(a+b)=0,求值:sin(π+2a+b)-cos(-π/2+2a+3b)
已知向量a=(sin(A+B)/2,cos(A-B)/2-3根号2/4) 向量b=(5/4sin(A+B)/2,cos(
已知Cos(a-b/2)=-1/9,Sin(a/2-b)=2/3,0
已知:tan a,tan b是方程X^2+4X+3=0的两个根,求3cos^2(a+b)+sin(a+b)*cos(a+
已知cos(2a-b)=-11/14,sin(a-2b)=(4√3)/7,且π/4
若sin^4a/sin^2b+cos^4a/cos^2b=1,证明sin^4b/sin^2a+cos^4b/cos^2a
已知0<A<π/2<B<π,cos(B-π/4)=1/3,sin(A+B)=4/5求cos(a+
已知向量a=(cosα,sinα) b=(cosβ,sinβ) |a+b|=2|a-b|
已知向量a=(sinα+cosα,√2sinα),b=(cosα-sinα,√2cosα),a∈[0,π/2],且
已知向量a=(cosα,sinα),b=(cosβ,sinβ),|a-2b|=|√2a+b|,则cos(α-β)=___
已知cos(a+b)=0,求证:sin(a+2b)=sina