Introduction to Differential Equations Fall 2023)

(Math 305, MWF 1:00-1:50PM, EGRA 420)

9.     Tutoring session: ???

### Instructor:  Dr. Dashun Xu

Office: 273 Neckers Hall A Wing
Office Hours: MWF 8:30-9:50am, 2:00pm-2:50pm, or by appointment

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

Zoom meeting room: 222 336 4190

### Textbook:Elementary Differential Equations & Boundary Value Problems, by Boyce and  DiPrima 10th ed

 90   A 80   B 70   C 60   D 59   F

 Midterm exams 35 Homework 25 Final 32 Attendance (deduct 1 point per missed class meeting) 8

Important dates

 Semester Classes Begin Monday, August 21 Last Day to Register Sunday, August 27 Last Day to drop w/ Reg. Office Friday, September 1 Last Day to Drop with Refund Sunday, September 3 Labor Day Holiday Monday, September 4 Last Day to Drop w/o Refund Sunday, October 29 Thanksgiving Break Sat, Nov 18 – Sun, Nov 26 Thanksgiving Holiday Thurs, Nov 23 – Fri, Nov 24 Final Examinations Mon, Dec 11 – Fri, Dec 15

### All assignments will be collected every Fridayin 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 Announcement 1 and 2 posted above. Due on Fri in class Please use the 10th edition of the textbook to do the homework problems. Otherwise, will be marked wrong! Week 2 1.3: 1-6, 8, 9;; 2.1: find the general sol. to 1,3,5,7 2.1: (find the general solutions, i.e. part c ) 9,11, 13, 15,   2.2: 1, 2, 5, 6, 7, 13(a,c) Due on Fri.   Please donot forget to staple your homework sheets together.   This webpage is updated according to the lecture pace on MWF. That is, you can get all HW due on each Fri till Wed after class. Week 3 2.1: 17, 19;; 2.2: find the solution to 14, 22; 2.6: 3, 7, 11, 15 Week 4 2.6: 9, 13 (find the solution); 2.6: (optional: 21; 22,) 2.6: 25, 26, 27, 28, 30;   2.4:  2, 5, 7, 11 Practice exam 1 (for you to review Chap 2)   HW due on Fri. Week 5 2.4:  28, 29, 30, 31   2.5: 3, 4, 7, 10 HW due on Fri.   Exam delayed to Week 6 Fri.   I will check your Practice Exam 1 on Wed. in class   Collect Practice Exam 1 on Fri. Week 6 3.1: 1, 3, 9, 13, 15, 20 3.2:   9,  13, Optional: 3, 5, 11, 26 HW also due on Fri.   Exam on Fri. 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. 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

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.