设(x,y),平行：2x-(-1)y=0,x^2+y^2=1.垂直：(-1)x+2y=0,x^2+y^2=1,解得：平行：(√5/5,-2√5/5)或者
(-√5/5,2√5/5),垂直：(2√5/5,√5/5)或者(-2√5/5,-√5/5)