variational principles的用法和樣例：
例句
- Variational principles play an important role in the formulation of many problems of mathematical physics.
變分原理現在許多數學物理的表述中起著重要作用。 - In this paper the elastic and elastoplastic interal forces of Cable dome strueture are analysed by the energy Variational principle.
本文採用能量變分原理分析拉索穹頂結構的彈性和彈塑性內力。
