3.25.3 Can you answer these questions?

3.25.3.1 Drawing manifolds in tikz
3.25.3.2 Combine -Triangle[left] and -Triangle[width=x]
3.25.3.3 Problem with sans serif using LibertinusT1math

Can you answer these?

3.25.3.1 Drawing manifolds in tikz

https://tex.stackexchange.com/questions/382762/drawing-manifolds-in-tikz

I know that there are other posts here addressing this issue, but none of them really made me able to draw the picture i have added below. I'm quite new to TikZ, so I would love to get some help with  ...
 
- asked by QuantumMechanic 4votes
3.25.3.2 Combine -Triangle[left] and -Triangle[width=x]

https://tex.stackexchange.com/questions/383395/combine-triangleleft-and-trianglewidth-x

Is it possible to combine the left and right option for arrows with options like length and witdth? Ia^\200\231d like to create an path ending in a 45A^Degree angle like this: 
So I tried to combine the above  ...
                                                                                  

                                                                                  
 
- asked by Tobi 3votes
3.25.3.3 Problem with sans serif using LibertinusT1math

https://tex.stackexchange.com/questions/383008/problem-with-sans-serif-using-libertinust1math

I like to use the text font Libertine and math font LibertinusT1Math. 
Is there a way to setup the math font LibertinusT1Math globally to sans serif? 
In my example I tried out a local switch 
...
 
- asked by Thomas 2votes