Explaining Expression 7.3 in Nother's Theorem and Invariance Under Translation

[hawaiifiver]

Hello,

I working through my notes on Nother's theorem and invariance under translation. I don't understand how they get expression 7.3, from the line before 7.3 (see attachment). Can anyone explain.

Thanks.

 

[oli4]

Hi hawaiifiver !
You mean the part where the Chasles relation is used to get from one line to the other ?
(integral from a to c is integral from a to b + integral from b to c (plus one of those integrals is reverted, that is integral from a to b is 'minus' integral from b to a)) ?
Cheers...