Here are the changes made in Version 2 of my notes about line integrals etc.

1. In some formulae "dy" has been changed to "dt".
(Thanks Yahel for noticing my mistake here.)

2. I have added a short remark at the very end of the document, explaining how
to generalize the definition and calculation of line integrals to the case
of certain curves which have a finite number of "corners" ("pinot"), i.e. points
where there is no tangent, where the components of the parametric representation do
not have continuous derivatives.