1.
If a×b×c=0\vec{a} \times \vec{b} \times \vec{c} = 0, a×b+b×c+c×a=6(b×c)\vec{a} \times \vec{b} + \vec{b} \times \vec{c} + \vec{c} \times \vec{a} = 6(\vec{b} \times \vec{c}), then the locus of the point (x,y)(x, y) is