Integrals

Hi /sci/

I'm having orals for a french computer engineering school (i'm french). Amongst those orals, there is a maths oral. The thing is, we didn't study integrals in class yet. And the book is f*** stupid. So could anybody clearly explain to me what integrals are, how they work, etc.

Thanks a lot ;)

integrals are (basically) the reversal of differentiation.
d/dx(2x)=2
integral(2x)=x^2 + k
where k is some unknown constant
Obviously, they become rather more complex, and may have multiple different solutions.
Does that help any?
also:
http://fr.wikipedia.org/wiki/Int%C3%A9grale