I'm very much interested in the thread about "Feynmans Calculus" (having read the books, too). The problem is I don't understand quite some of the stuff, because I don't have the necessary fundamental knowledge.

So I thought to confront you with some lower level questions:

How do you solve this: [tex]\int\ e^{(-x^2)} dx[/tex] ?

It seems that [tex]\int_{-\infty} ^\infty e^{(-x^2)} dx=\sqrt{\Pi}[/tex]. Why is that?

I honestly have no clou.

I would be very thankful if somebody could explain this to me (then I could also continue to see wether the rest of my questions still makes sense...).

Best regards and thank you in advance

cliowa