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
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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)求sin2a和tan2a的值 (2)求cos(a+2b)的值
![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](/uploads/image/z/4736103-15-3.jpg?t=%E5%B7%B2%E7%9F%A5sina%2Bcosa%3D%283%E6%A0%B9%E5%8F%B75%29%2F5%2Ca%E2%88%88%280%2C%CF%80%2F4%29%2Csin%28b-%CF%80%2F4%29%3D3%2F5%2Cb%E2%88%88%28%CF%80%2F4%2C%CF%80%2F2%29+%EF%BC%881)
![](http://img.wesiedu.com/upload/1/98/198faa38bd2bf18387a0339e680d57d1.jpg)
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)