The reading and homework for Week #2 have been posted. Follow the link from the Schedule Page of the course website.
There are a couple "homemade" problems this week. They are available in a pdf file linked from the assignment page. You only need to complete the first two (this week). Early next week I'll post a new pdf file with only those problems you need to complete.
UPDATE: For problem 2.3.15 you will want to use dfield, or some other technology. You will find it quite difficult to complete the integration by hand. Additionally, problem 2.5.7(b) makes some comments about the phase line for the differential equation in question. You should actually show the phase line in your solution. Problem 2.5.20(b) is also simplified greatly by looking at the phase line, though it is not, strictly speaking, necessary.