在空间四边形ABCD中,AB=CD,BC=AD,AD⊥DC,AD⊥BC,AB⊥BC,求证:BD是AD,BC的公垂线

AD⊥BC =>AD⊥平面BCD=>AD⊥BD
AD⊥DC AD⊥BC
=>BD是AD,BC的公垂线
BC⊥AD =>BC⊥平面ABD=>BC⊥BD
BC⊥AB