Problems for next week and a draft write-up for diff.eq. systems

Problems for next week posted, though I have a gut feeling that it might be a bit too much; if you feel that you have done the week's workload with two of the problems left, chances are that others & Sondre will agree with you. The leftovers will be assigned for the subsequent seminar. 

Also, I uploaded a draft write-up of differential equation systems (Thursday's and next Tuesday's topic). I might have to update it.