第二节正弦函数和余弦函数的定义及诱导公式
1.若cosα=-,α∈(,π,则tanα=________.
2.若sinθ=-,tanθ>0,则cosθ=________.
3.若sin(+α=,则cos(-α=________.
4.已知sin x=2cos x,则=______.
5.若cos2θ+cosθ=0,则sin2θ+sinθ=________.
6.已知sin(π-αcos(-8π-α=,且α∈(,,求cosα,sinα的值.
B组
1.已知sin x=2cos x,则sin2x+1=________.
2. cos=________.
3.已知sinα=,且α∈(,π,那么的值等于________.
4.若tanα=2,则+cos2α=_____________.
5.已知tan x=sin(x+,则sin x=______________.
6.若θ∈[0,π,且cosθ(sinθ+cosθ=1,则θ=________.
7.已知sin(α+=,则cos(α+的值等于________.
8.若cosα+2sinα=-,则tanα=________.
9.已知f(α=,则f(-的值为________.
10.求sin(2nπ+·cos(nπ+(n∈Z的值.
11.在△ABC中,若sin(2π-A=-sin(π-B,cos A=-cos(π-B,求△ABC的三内角.12.已知向量a=(,1,向量b=(sinα-m,cosα.
(1若a∥b,且α∈[0,2π,将m表示为α的函数,并求m的最小值及相应的α值;
(2若a⊥b,且m=0,求的值.