Confirming Principal Axis of Inertia of Rigid Body by Analytic Approach

In rigid body mechanics, confirming the principal axis of inertia of rigid body is particularly important, its calculation can be made to be simplified and favorable to study the nature and movement law of rigid body. The methods and steps of confirming the principal axis of inertia by analytic approach were presented, starting from the definition of the principal axis of inertia and through strict derivation. The method of using analytic approach to confirm the principal axis of inertia is suitable in extensive range, universal, and especially for those problems having no obvious symmetry.