9.8.3 Can you answer these questions?

9.8.3.1 Why is the dot operator not just matrix multiplication?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=280511

It seems to me Mathematica does not have an inbuilt matrix multiplication operator. The dot operator fails as such, as is even noted under "Possible Issues" in its documentation it ... 
[matrix] [language-design] [dot]
 

asked by cbartondock https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=76992 Score of 1

9.8.3.2 Grid Problem: Combining Item[] with SpanFromLeft/Above

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=280562

I'm trying to lay-out a  Grid  with various entry-specific  Frame  settings.  In my case, using ... 
[front-end] [gui-construction] [grid-layouts] [frame] [grid-lines]
 

asked by Sean https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=76328 Score of 2

9.8.3.3 Rasterize and export 3d graphic

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=280498

I want to Rasterize a 3D model, for which I need a high count of Plotpoints. 
I rasterize the graphic and export it as a pdf in the following way: 
... 
[plotting] [rendering]
 

asked by mathematica_guy https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=86803 Score of 1