a=(√3,-1),b=(1/2.√3/2),x=a+(t^2-3)b,y=-ka+tb,x⊥y,则向量x•y=0,(a+bt^2-3b)•(-ka+tb)=0,-ka^2-kabt^2+3abk+tab+t^3b^2-3tb^2=0,其中,a^2=3+1=4,b^2=1,a•b=-√3/2+√3/2=0,(a+bt^2-3b)•(-ka+tb)=-4k+t^3-3t=0,所以k=(t^3-3t)/4.