Not too easy. Not too difficult.
Differential Equations is typically considered an advanced math course by most students, and so the ability to do well comes in two parts; overcoming the difficult subject and overcoming the fear of the subject itself. Because of this, it is important to have a teacher as great as Pennell to really break the subject material down for you.
Applied Calculus definitely is something that is interesting to see for the first time. Looking back at the obscure word problems given in your first two years of Calculus, it sometimes could be difficult to truly understand a concept without an applied example. This course gives many applied examples to finally understand the importance of calculus in the real world.
Hours per week:
Advice for students:
If at all possible, take the course with Professor Pennell. He is a great teacher, as well as a fair grader. I took Diff EQs before I took Calculus III and had no issues, so if the possibility arises and this is the situation, still go for it.