Hi Tsevelee,
I gave it a try to provide answers to your 4 first questions. They brought me back more than 7 years ago ;-)
I am confident in having the right answers for the exercises 1 and 3.
For the exercise 2, I think I missed something, because the solution seems to be to easy...
For the exercise 4, I am not sure I have taken the right approach, but it does not look bad.
Feel free to have a look at the attach PDF for my solutions, and I invite anyone to comment and correct my answers.
Best regards,
Sebastien
