10.31.3 Can you answer these questions?

10.31.3.1 How to derive this vector analysis equation?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=306920

How to use mathematica to derive this vector equation: 
\begin{equation} 
\nabla \times (\mathbf{A} \times \mathbf{B}) = (\mathbf{B} \cdot \nabla) \mathbf{A} - (\mathbf{A} \cdot \nabla) \mathbf{B} + \... 
[simplifying-expressions] [vector-calculus]
 

asked by Toboraton https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=101790 Score of 1

answered by Roland F https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=92018 Score of 0

10.31.3.2 Replacement of strings within lists

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=306948

i have a string list: 
 lis = {"a",{"b","c"},"d"} 
 
...and would like to replace "c" with "Q", to give 
<... 
[string-manipulation]
 

asked by Suite401 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=42475 Score of 1

10.31.3.3 Poincare section using Hamiltonian formalism

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=306982

I'm trying to plot Poincaré surface of sections, using Hamiltonian formalism, for a system with 3 degrees of freedom. I have written a code for this. The code provides results for the integration of ... 
[differential-equations] [numerical-integration] [physics] [nonlinear] [sow-reap]
 

asked by MMS https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=63380 Score of 1