7.19.1 Top new questions this week

7.19.1.1 Total flux of the gradient of the numerical solution of a PDE through a surface
7.19.1.2 What should I make of "Simplify: Time spent on a transformation exceeded -4.03955*10^12 seconds"?
7.19.1.3 Barchart with statistics as labels
7.19.1.4 Challenge: Computing the Fourier Series of a List Plot!
7.19.1.5 How to solve this PDE for steady state?
7.19.1.6 How to write that Lyapunov function?
7.19.1.7 How to rotate a circle around the y-axis and calculate the volume of the 3D solid?
7.19.1.1 Total flux of the gradient of the numerical solution of a PDE through a surface

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=246808

Trying to solve the following PDE with BC  T==1  on a spherical cap of a unit sphere and  T==0  at infinity (approximated as ... 
[differential-equations] [calculus-and-analysis] [numerical-integration] [finite-element-method] [heat-transfer-equation]
 
asked by umby https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=58367 11 votes
answered by Tim Laska https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=61809 12 votes
7.19.1.2 What should I make of "Simplify: Time spent on a transformation exceeded -4.03955*10^12 seconds"?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=247043

Running version "12.0.0 for Microsoft Windows (64-bit) (April 6, 2019)", in case that matters. I fed Mathematica the command 
... 
[warning-messages]
 
asked by A. Howells https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=80314 8 votes
answered by JimB https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=19758 4 votes
7.19.1.3 Barchart with statistics as labels

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=246820

The following code (thanks to @Jagra): 
... 
[charts] [code-review] [code-request]
 
asked by Tugrul Temel https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=60365 7 votes
answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 8 votes
7.19.1.4 Challenge: Computing the Fourier Series of a List Plot!

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=247081

I have a bunch of data points (copied from Mathematica below), which I have 'ListPlotted' 
I would now like to compute the Fourier series of this function (after doing a Fourier transform I assume? Or ... 
[plotting] [calculus-and-analysis] [numerical-integration] [fourier-analysis]
 
asked by rdx https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=80329 6 votes
answered by Daniel Lichtblau https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=51 3 votes
7.19.1.5 How to solve this PDE for steady state?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=247031

... 
[differential-equations] [numerical-integration] [finite-element-method]
 
asked by psimeson https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=29312 6 votes
answered by Chris K https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=6358 8 votes
7.19.1.6 How to write that Lyapunov function?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=247073

For didactic purpose I investigate the stability of the ODEs system  {x'[t] == x[t] + y[t], y'[t] == -5 x[t] - 2 y[t]} . 
Its stream plot 
... 
[differential-equations]
 
asked by user64494 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=7152 6 votes
answered by Michael E2 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4999 4 votes
7.19.1.7 How to rotate a circle around the y-axis and calculate the volume of the 3D solid?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=246948

How do I rotate the equation ${(x-5)^2}+{y^2}={3^2}$ around the y-axis and calculate the volume of the plotted 3D solid? 
I tried the code below but the result doesn't work. 
... 
[calculus-and-analysis] [scripting]
 
asked by AndreaNeg https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=80293 6 votes
answered by cvgmt https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=72111 5 votes