Mathematica's default way of representing derivatives is to express them with respect to a function's input slot. But what if I want to use the chain rule? To replace df(x)/dx with df(0.5 y)/dy 0.5, where x=2y. What is the Mathematica way of doing this? Is the proper way using [esc] pd [esc] [Ctrl][-][x]?
I'm following a quantum mechanics lecture and trying to write down the math on the slides to Mathematica. I just can't figure out how to express the steps in Mathematica code. I'm really struggling with the first slide of https://www.youtube.com/watch?v=DDvnybFrVlE&index=21&list=PLoRUNeJAicqZ_qLKTrdbXvvg_WTtFK_Ds
Apparently, the first step in solving a differential equation is often a change of variables, which he proceeds to do on the first slide. He uses the chain rule to change the variable that psi is differentiated with respect to.
D[f[y/2], y]? It's not clear to me what code you're starting with and how you want to transform it. Well, that's what I'm assuming you want to do. $\endgroup$
f'[x] /. f -> (f[#/2] &), but it keeps
xinstead of substituting
Dvia a shortcut, which is described in the first bullet point under "Details and Options" section of the docs for