A simple derivation of cosmological formulas

spoirier

Hello. I just added to my site a simple reasoning that quickly justifies the basic formulas of cosmology in General Relativity (Friedmann differential equations, assuming homogeneity and so on, including the role of the cosmological constant), without any heavy formalism (only assuming basic properties of curved geometry and mechanics):
http://settheory.net/cosmology
If you find any error, or if you have a better notation to suggest, please tell me; if mentors think it can be suitable to include in the list of Advanced Physics Learning Materials, please do. Thanks.