How do I solve this problem?

[Doomknightx9]

I have no idea how to do this. Can i get some steps and a solution please

 

[Joppy]

Surely you don't have no idea. Try reading through the question and every time you come across something you aren't sure about, jot it down and investigate it independently. For example, what is Stokes' theorem? What does it say and when do we use it?