5. Let two regular tetrahedra $P-A B C$ and $Q-A B C$ be inscribed in the same sphere. If the dihedral angle between a lateral face and the base of the regular tetrahedron $P-A B C$ is $45^{\circ}$, then the tangent value of the dihedral angle between a lateral face and the base of the regular tetrahedron $Q-A B C$ is $\qquad$ .