1. Computer Science 20 Discrete Mathematics for Computer Science 1 All the Math you need for your Computer Science courses that you won’t learn in your Math Courses CS20/CSCI E-20 w/thanks to Al Meyer

2. Some Topics Formal logic (p ∨ q) ∧ ¬(p ∧ q) Graphs and digraphs Probability Counting Number theory p ≡ q r (mod m) … see the “placement test” on the web site 2 a f c d b CS20/CSCI E-20 w/thanks to Al Meyer

3. Skills!!! How to do proofs –By contradiction –By induction –…–… How to read and write mathematics –And typeset! How to collaborate How to present clearly and persuasively 3 CS20/CSCI E-20 w/thanks to Al Meyer

4. 3 Principles of Course Philosophy 1.Learning, not competing –Absolute grading standards – no “curve” –Solutions will be available – study them! 2.Learn by doing, not by listening –Learn by collaborating 3.Consume the course material in many small bites –Which requires keeping up 4 CS20/CSCI E-20 w/thanks to Al Meyer

5. Typical Class Day Before each class: –Reading and check-in problems (30-60 mins) –Watch mini-lecture (~20 minutes) In class –Start at 10:10 sharp! Be here! –Announcements –Sample problem (10 minutes) –Collaborative problem solving in groups of 4 (40 mins) Weekly –Homework (3-5 hours) So class week = –3 hours class time –~8 hours out-of-class time Most readings from MIT course notes 5 CS20/CSCI E-20 w/thanks to Al Meyer

6. Requirements Attendance is mandatory! –3 “free” unexcused absences, see home page for details Official/emergency absences ⇒ email harvard-cs20@googlegroups.com –Class begins at 10:10 sharp Two 50-minute midterm exams –First on 22 February –Second on 25 March Weekly homework –Late policy: See home page 3-hour final during exam period 6 CS20/CSCI E-20 w/thanks to Al Meyer

7. Should You Take CS20? Prep for CS121 and CS124 There is a mini-self-test on the course Canvas site Don’t take it if you are doing Math 25 or probably Math 23 either Don’t take it AFTER CS121 or CS124 Questions? Use Piazza, or email harvard-cs20@googlegroups.com, which goes to the whole course staff harvard-cs20@googlegroups.com 7 CS20/CSCI E-20 w/thanks to Al Meyer

8. Grading Mix Homework40% 2 Midterms20% Final exam30% Participation 5% Check-in questions 5% (Poor attendance: Exclusion or failure) 8 CS20/CSCI E-20 w/thanks to Al Meyer

9. And now – the course in action! 9 CS20/CSCI E-20 w/thanks to Al Meyer