Introduction to Differential Equations Spring 2023)

(Math 305, MWF 8:00-8:50PM, EGRA 220)

9.     Turtoring session: Monday - Thursday from 5-9 p.m in Lib 680 (tutors and computers)

### Instructor:  Dr. Dashun Xu

Office: 273 Neckers Hall A Wing
Office Hours: MWF 12:50-2:50pm or by appointment, 8:50am-9:20am

E-mail: dashunxu@siu.edu  Phone: 453-6512

Zoom meeting room: 222 336 4190

### Syllabus (Attachment for more useful webpage and dates)

Last Day to drop with Refund: 01/27;  Last Day to drop with no Refund (W grade): 04/02

### All assignments will be collected every Friday in class and only a few questions in each assignment will be graded. Late homework will not be accepted. The followings are problems assigned last time. I will update these problems after each class meeting. Please make sure to refresh the webpage

 Date Homework Week 1 Week 2 1.3: 1-6, 8, 9;; 2.1: find the general sol. to 1,3,5,7, 8 2.1: (find the general solutions, i.e. part c ) 9,11, 13, 15, 17, 19;; Due on Fri.   Please donot forget to staple your homework sheets together.   This webpage is updated according to the lecture pace in the afternoon (after 2pm) on MWF. That is, you can get all HW due on each Fri till  Wed after class. Week 3 2.1: 8, 20; 2..2: 1, 2, 5, 6, 7, 13(a,c), 2.2: find the solution to 14, 22; 2.6: 2, 3, 4, 5, HW due on Fri. Week 4 2.6: 7, 8, 2.6: 9, 13, 14 (find the solution); 2.6: 18, 21; 22, 2.6: 25, 26, 27, 28, 30; Practice exam 1 (for you to review Chap 2)   HW due on Fri. Week 5 2.4:  2, 5, 7, 2.4: 11, 28, 29, 30, 31   2.5: 3, 4, 7, 10 HW due on Fri.   Please use the 10th edition of the testbook to do the homework problems. Otherwise, be marked wrong! Week 6 3.1: 1, 3, 9, 13, 15, 20 Exam on Fri!!!   Due on Fri.   Collect Announcements 1, 2, 3   (separate from HW)!!! Week 7 3.2:   9,  13, Optional: 3, 5, 11, 26     3.3: 7, 11, 17, 20, 21 Optional 9, 12, 15, 19 Since some student complained that there are too many homework problems, I moved some to optional. I still strongly recommend you to do all if possible.   Due on Fri. Week 8 3.4: 7, 9, 11, 13, 23, 27, 29, Optional: 12, 25, 28, 30,   3.3: 21     3.5: 1, 5, 3.5: 21(a, donot solve),  22a, Week 9 3.5:  3, 7,  9, 3.5: 16, 17,  23a, 25a, 27a; Optional: 6, 8, 10, 18, 19   3.6:  5, 7,  13,  17, optional: 3, 4, 14, 16, 18 Due on Fri. Week 10 4.1: optional: 14, 15, 16   4.2: 11, 14, 22, 31, find solution to IVP: 32; optional: 13, 16, 18, 19, 24, 35 Week 11 4.2: 17, find solution to IVP: 29   4.3: 2, 3, 6, 9, 4.3: 13,  15, 16, 17,  Optional: 1, 10, 12, 14, 16, 18 HW due on Fri. Week 12 4.4: 2, 3,  9   10.1: 1, 3, 4 10.1: 14, 16, 18 Optional: 2, 5, Homework due on Fri. Currently Week 13 10.2: 13, 15 HW due also on Fri. Second Exam on Fri!!! Covering Chap3, 4, and 10.1. Week 14 10.2: 14, 16 10.3: 1, 2, 3, 10.3: 7a, 9a, 11a Due on Fri 10.4: 7, 8, 9, 15, 16, 24(a,b)  10.5: 1, 2, 5, 6,     Optional: 10.5: 7, 8 after watching the video for 10.5. Week 15 Practice for the final: Midterm exams and their practice exams, homework problems for Chap10.2—10.5 Final exam: Thur. 8am, May 11

Study Hint:

Find at least one or two other students from the class with whom you can regularly do homework and prepare for exams. Your classmates are perhaps the least used and arguably your best resource. An efficient and effective study group will streamline homework and study time and greatly improve your written and spoken communication. The best time to use your classmates as study/homework partners is after you have made an honest effort on your own to solve the problems using your own wits, knowledge, and experience. When you encounter an unsolvable problem, don't give up too soon on it. Being stumped is an opportunity for mathematical growth and insight, even if you never solve the problem on your own. If you seek help prematurely, you will never know if you could have solved a tough problem without outside assistance.