文档分类
南航数学物理方程
u ( x, t ) u ( x + dx, t ) u ( x, t ) T ρ gdx ≈ ρ dx 2 x x t 22 2 u ( x, t ) u ( x, t ) T x 2 ρ g dx ≈ ρ t 2 dx T u ( x, t ) u ( x, t ) ≈ +g 2 2 ρ x t2 2