Sorry to cut in the thread like that but i beleive i can add something that might help ya.
I have studied what your talking about McNeo and I must say at first it seams hard and then it gets easyier
The wavy thing is an integration sign and the number under it is the start of the section you wish to do the integration on and the top one is the end.
Basicaly an integration is the surface under a curve if you were wondering and a derivation if a "tangente" slope.(french is my native language so please someone translate the quoted word...)
Im not sure all your examples are solved correctly since i barely checked em but they look ok.
