# Ordinary Differential Equations

Warren Weaver Hall, room 202, Tuesdays and Thursdays, 11am - 12:15pm
Courant Institute of Mathematical Sciences
New York University
Fall Semester, 2012

There will be regular (approximately weekly) assignments that will be posted here and announced via email. Assignments may be posted before we have covered all the material, allowing you to start working on some of the problems early.

### Logistics

Homework assignments will most often be problems from the primary textbook by Coddington, unless indicated otherwise. They will be posted here (in the format chapter.section.problem.part) along with the due date and the number of points for each problem. The points from all the assignments will simply be added up to form the final grade.

Homeworks should be turned in at the beginning of class, or if you cannot attend, before class in person or under the door of the instructor (1016 WWH). No late assignments will be accepted. Homeworks will be returned the first class of the following week.

NYU academic integrity policies will be strictly enforced for homework assignments. No group work is allowed: each assignment must be individual work.

## Assignments

### 1. (50pts) Linear 1st Order ODEs [due Thursday Sept. 13th]

Problems from Coddington:
• 1.3.1(c,d) 2.5+2.5=5pts
• 1.6.1(b,c) 2.5+2.5=5pts
• 1.6.6(a,b) 5+5=10pts
• 1.7.1(b) 5pts
• 1.7.2(a,b) 5+5=10pts
• 1.7.5(a,b) 10+5=15pts

### 2. (65pts) Constant-coefficient second-order ODEs [due Thursday Sept. 20th]

Problems from Coddington:
• 2.2.2(a,b,c) 2+2+1=5pts
• 2.2.9 = 5pts
• 2.3.5 = 7.5pts
• 2.4.1(b,c,f) 2.5+2.5+5 pts = 10pts
• 2.4.2(a,b) 7.5+7.5 = 15pts
• 2.4.8 = 5pts
• 2.6.1(f,j)  5+5=10pts
• 2.6.4(a,b) 2.5+5=7.5pts

### 3. (50pts) Variable-coefficient second-order ODEs and complex numbers [due Thursday Sept. 27th]

Problems from Coddington:
• 3.3.1(a,b,c) 2.5+5+2.5=10pts
• 3.5.1(b,f) 5+5=10pts
• 3.6.2 = 10pts [Note: The rhs is not clearly printed, use x^2]
• 0.2.2(b,c) = 2.5 + 2.5 = 5pts
• 0.4.1(b,e) = 2.5 + 2.5 = 5pts
• 0.6.1 = 5pts
• 0.6.4 = 5pts

### 4. (65pts) Nonlinear ODEs and simple series methods [due Tuesday Oct. 9th, no homework following two weeks]

Problems from Coddington:
• 4.2.1(a,d) 2.5 +5 = 7.5 pts
• 5.2.1(c,d) 5 + 5 = 10 pts
• 5.2.3(a,b) 5 + 5 = 10 pts
• 5.3.1(a,b,f) 5 + 2.5 +5 = 12.5 pts
• 5.3.2.a = 10 pts
• 3.7.3 = 15 pts