MATH 1610 Lecture 3: Day3 Sept16.docx

Let A, B, C and D denote four distinct points in the plane. Let u rightarrow AB denote the vector pointing from A to B, and similarly u rightarrow BC points from B to C while u rightarrow CD points from C to D and u rightarrow DA points from D back to A. Evaluate the vector sum u rightarrow AB + u rightarrow BC + u rightarrow CD + u rightarrow DA.