5.22.3 Can you answer these questions?

5.22.3.1 TikZ Feynman basic QED vertex misalignment

https://tex.stackexchange.com/landing/r/newsletter?cta=question&id=496732

As the title says, I'm trying to draw the basic vertex of QED with TikZ Feynman, but whenever I run the following code in LuaLaTeX through TeXStudio 
\documentclass[a4paper]{article} 
... 
[tikz-feynman]
 

asked by ErickShock https://tex.stackexchange.com/landing/r/newsletter?cta=user&id=187665 1 vote

5.22.3.2 How can I use Garamond Premier Pro's own glyphs for e.g. square root in mathmode (using lualatex)?

https://tex.stackexchange.com/landing/r/newsletter?cta=question&id=497148

I'm using lualatex (TeXlive 2019) and the font Garamond Premier Pro, which 
(shown in the screenshot, taken using fontforge) provides special glyphs for the following mathematical symbols: 
n-array  ... 
[fontspec] [unicode-math]
                                                                                  

                                                                                  
 

asked by lAtExFaN https://tex.stackexchange.com/landing/r/newsletter?cta=user&id=112503 1 vote

5.22.3.3 Unknown graphics extension eps

https://tex.stackexchange.com/landing/r/newsletter?cta=question&id=496967

When I try to compile my tex file with an eps figure, I get the error message "Unknown graphics extension eps". 
I don't understand why: I write \usepackage{epstopdf} in the preamble so there should be  ... 
[graphics] [pdftex] [eps]
 

asked by Alessandro https://tex.stackexchange.com/landing/r/newsletter?cta=user&id=165153 1 vote