文 [1 ]给出了三面角中棱与面所成角与三面角之间的关系如下 :定理 1　在三面角S—A1 B1 C1 中 ,三个面角∠C1 SB1 =α ,∠A1 SC1 =β,∠A1 SB1 =γ ,且棱SA1 和平面C1 SB1 所成的棱面角为θ1 ,棱SB1 和平面A1 SC1 所成的棱面角为θ2 ,棱SC1 与平面A1 SB1 所成棱面角为θ3,则co The relationship between the angle formed by the ribs and the plane and the trihedral angle in the trihedral angle is given by [1]. Theorem 1 In the trihedral angle S-A1 B1 C1, the three plane angles ∠C1 SB1 =α, ∠A1 SC1 =β, ∠A1 SB1 =γ, and the angle of the facet of the edge SA1 and the plane C1 SB1 is θ1, the facet angle of the edge SB1 and the plane A1 SC1 is θ2, and the facet of the ridge SC1 and the plane A1 SB1 The angle is θ3, then co