About 3 Integral Calculus's question. The text book I used is "Advanced calculus" by Folland. Chapter 1 "Setting the Stage" ，Chapter 2 "Differential Calculus" , Chapter 3 "The Implicit Function Theorem and its Applications ", Chapter 4 " Integral Calculus" and Chapter 5 "Line and Surface Integrals; Vector Analysis" maybe helpful for you. The question, the PDF of the "Advanced calculus" 's solution manual and the photos of class notes will be attached. And please pay attention, after I accpted the answers, I will give the amount of $50 as tips. Thanks. Thanks a lot.