solve 5.3.42 and 5.3.43

[tenick]

added proof for problem 5.3.42 and 5.3.43
i have some illustrations/tables along with the proof so you can review the proof in the attached PDFs instead
(NOTE: i didn't add parskip package in the attached PDFs so indentation looks weird)

problem_5.3.42_proof.pdf
problem_5.3.43_proof.pdf

[spamegg1]

Thanks a lot! ❤️

Ignore the build failing, it's something I'll figure out later.

I've read 5.3.42 and I think the idea of the proof is right; but it's written in a bit confusing way. We'll have to write it more clearly, and make the assignment of the distances more direct and explicit.

I'll get back to you on that. (Kind of busy these days, might take a while!)

5.3.43 looks fine 👍