Here are the solved exercises.
Here are solutions to some of the exercises.
Week 35: Solutions to all exercises except those involving R.
Week 37: Solutions to the exercises can be found in here.
Week 38: Solutions to almost all exercises. Additional exercise 5 is an R-exercise. I have made an .Rmd file covering it. This is a file format handy for presenting R code together with plots and mathematics. You can find it here. For information about how to read these files, see e.g. this site. A solution in pdf is here. Edit: There's an error in exercise 11. Here $s = \alpha(\phi)t$ is correct, not the other way around.
Week 40: Solutions.
Week 42: Solutions.
Week 43: Solutions.
Week 44: Solutions.
Week 45: Solutions.
Week 47: Solutions.