Feynman would be proud

Feynman would be proud

We calculate the integral x^n exp(-x) from 0 to infinity using Feynman's technique. This is a must see for all the calculus students out there, enjoy!

[circlesofMATH]

Great idea! Only one thing, the first integral is I believe Gamma(N+1)=N!, and not Gamma(N).

[holyshit]

If we assume than n is an integer it is enough to use by parts to derive recurrence relation
No need for Gamma function or Leibniz rule for differentiating under integral sign

[utuberaj]

Superb trick Dr Peyam.
I was missing your videos for some time. Now, you're back as Dr. 'cool' Peyam❤

[SystemsMedicine]

Dr.P. It’s good to see you’ve returned…

[Platechicken]

Beautiful, never thought of solving it this way.

[edmundwoolliams]

"B-b-but Mr Feynman... j-just how did you ever solve it?..."

"It's easy. Just differentiate under the integral sign 😏"

[alipourzand]

Pure magic! As my physics professor in university said: "il n'y a que les em**rdeurs qui inventent des formules compliquées!" ☺

[cheeseparis]

I want to travel back in time and use this in an exam.

[chrissch.]

Sehr cool - den Trick kannte ich noch gar nicht, obwohl ich mich früher mit analytischer Zahlentheorie beschäftigt habe…🤣

[lamp]

We start by stating the integral= (N+1)! and with the Feynman method the same integral = N! Am I missing something?

[MS-cjuw]

It's Gamma (n+1) not Gemma(N),
Gamma (N+1)=N!

[justanotherguy]

I am trying to stay as far away from cool as possible. As a matter of fact, cool people do not like mathematics, which is one of the reasons I love it.

[bart]

Wait... Didn't you say at the start that it should be (n+1)! ?