(1)取AB中点E,连接SE,DE,1=EB//=CD,EBCD为矩形,DE⊥AB,SE⊥AB,AB⊥平面SED,AB⊥SD,SE=√3,DE=2,SD=1,DE²=SE²+SD²,
SE⊥SD,SD⊥面SAB.
(2)作SF⊥DE,FG⊥BC,BC⊥面SFG,tan∠SGF=√3/2,∠SGF=arctan√3/2为所求
(1)取AB中点E,连接SE,DE,1=EB//=CD,EBCD为矩形,DE⊥AB,SE⊥AB,AB⊥平面SED,AB⊥SD,SE=√3,DE=2,SD=1,DE²=SE²+SD²,
SE⊥SD,SD⊥面SAB.
(2)作SF⊥DE,FG⊥BC,BC⊥面SFG,tan∠SGF=√3/2,∠SGF=arctan√3/2为所求