18.02 assumes that the students have some basic understanding of vectors, but the class uses them quite a bit so we'll go over some review before diving right into the content that's covered in the class. If you've taken 8.01 already or are taking it right now, MITx should also have a great review on vectors under Week 1. On this page, we'l briefly go over the following topics:

1. What is a vector?
2. Adding and subtracting two vectors
3. Finding the length/magnitude of a vector
4. Finding a unit vector in the direction of a given vector 

1. What are vectors?
All vectors have two attributes: a magnitude, and a direction. For example, in physics you'll see that the mass of an object is not a vector because it has a magnitude, but no direction. On the other hand, the gravitational force on an object (its weight) is a vector because it has a magnitude, and a direction that points to the center of the Earth. In 18.02, we'll be