昆山做网站,徐州地产开发公司招聘,网站开发技术标准,项目建设流程向量场中的几个恒等式 
1.  ∇ 2 A  ∇ ∇ ⋅ A − ∇  ∇  A \nabla ^2 A \nabla \nabla\cdot A-\nabla \times\nabla\times A ∇2A∇∇⋅A−∇∇A 
2.  ∇ ⋅ ∇  A  0 \nabla \cdot \nabla \times A  0 ∇⋅∇A0 
3.  ∇  ∇ ϕ  0 \nabla \times \nabla \phi0 ∇∇ϕ0向量场中的几个恒等式
 
1.  ∇ 2 A = ∇ ∇ ⋅ A − ∇ × ∇ × A \nabla ^2 A =\nabla \nabla\cdot A-\nabla \times\nabla\times A ∇2A=∇∇⋅A−∇×∇×A
 
2.  ∇ ⋅ ∇ × A = 0 \nabla \cdot \nabla \times A = 0 ∇⋅∇×A=0
 
3.  ∇ × ∇ ϕ = 0 \nabla \times \nabla \phi=0 ∇×∇ϕ=0