Is there a reason why scientific papers rarely show derivation of an equation? I fail to see the any advantages ( besides savings latex hours for the authors) of this approach which is the standard way. Do editors get to see full derivations when one send papers to them? Why so secretive? Do these scientists live in the dark ages?
Usually papers have derivations, they just don't hold your hand through every step (which is what I'm guessing you are looking for), making it seem like they are making huge jumps in logic. It can be frustrating, especially when you are new to a field. But the more you learn, the less you'll need the details presented to you, as it will generally be understood. From an experts view, there is no point putting elementary derivations in every paper, they want to get to the good stuff.