This is something i don't remember what I'm supposed to do. So anyway here goes.
For example if my function was
xe^yx and i wanted to integrate with respect to dx
then i do an integration by parts with these variables:
u = x dv = e^yx
now my question is, when i try to find du do i differentiate with respect to x? same goes for dv, do i integrate with respect to dx?
suppose instead i chose
u = e^yx and dv = x
then du would be ye^yx?
Hopefully that was clear enough.