已知sina+cosa=(3根号5)/5,a∈(0,π/4),sin(b-π/4)=3/5,b∈(π/4,π/2) (1
已知sina+cosa=(3根号5)/5,a∈(0,π/4),sin(b-π/4)=3/5,b∈(π/4,π/2) (1
化简:sin(a-B)cosa-1/2[sin(2a+B)-sinB]=?已知cos(a-π/6)+sina=4√3/5
sin(a-B)cosa-1/2[sin(2a+B)-sinB]=?已知cos(a-π/6)+sina=4√3/5则si
若cos(a+B)*cosa+sin(a+B)*sina=-4/5,则sin(π/2-B)
已知sin(2π-a)=4/5,a∈(3/2π,2π),则(sina+cosa)/(sina-cosa)等于
(1)已知:sina+cosb=3/4,cosa+sinb=-5/4,求sin(a+b).
已知sin(a/2)=4/5,a∈(π,2π),求sina,cosa,tana.
已知sin(a/2)=4/5,a∈(π,2π),求sina,cosa,tana
已知a=(3,1),b=(sina,cosa),且a‖b,则(4sina-2cosa)/(5cosa+3sina)=
已知a=(3,1),b=(sina,cosa),且a∥b,则4sina-2cosa/5cosa+3sina=
已知sina+cosb=3/4,cosa+sinb=-5/4,求sin(a+b)
已知向量a=(cosa,sina),b=(根号2-sina,cosa),a∈(-π/2,π/2)