2 ms·
It’s interesting he mentions he doesn’t like contour integration since many integrals can be done either way. Feynman’s trick is equivalent to extending it int
by zeroonetwothree 11mo ago
It’s interesting he mentions he doesn’t like contour integration since many integrals can be done either way.
Feynman’s trick is equivalent to extending it into a double integral and then switching the order of integration.
- measurablefunc 11mo agoDon't forget to check for the necessary measurability & integrability of the sections (f(a, y), f(x, b)) before switching the order: https://en.wikipedia.org/wiki/Fubini%27s_theorem?useskin=vector https://en.wikipedia.org/wiki/Fubini%27s_theorem?useskin=vec....
- dunham 11mo agoThis reminds me of the "snake oil method" for generating functions. It's been many years, but I remember it as adding another sigma and then swapping them.
- amai 11mo agoContour integration is basically a double integral in disguise.