角α的终边过点(2sin6,-2cos6)则sinα= ?α=?

角α的终边过点(2sin6,-2cos6)
x=2sin6,y=-2cos6,r=√(x^2+Y^2)=
√[((2sin6)^2+(-2cos6)^2]=√4[(sin6)^2+(cos6)^2]
=√4×1=2
∴sinα=y/r=-2cos6/2=-cos6,
3π/2<6<2π
sinα=-cos6=sin(3π/2-6)
∴α=(3π/2)-6+2kπ(k∈Z)或
α=π-[(3π/2)-6]+2kπ→α=-π/2+6+2kπ(k∈Z)