Some statistics on the HW:
Low: 10
High: 100
Median 87.5
AVG 79.8
Mode: 100


Most common mistakes:
1. Many people either forgot or did not realize that in problem 1-6 you have
to problem the if and only if in both directions.
2. Several people attempted to prove the lines forming the edges of the 
parallelogram are parallel by showing that they do not intersect. This isn't 
enough in General Rn.
3. Also for 1-7 many people skipped parts of the problem that cost them 
varying amounts of points. 
4. One person made the unique argument that the parallelogram is a 
parallelogram because a parallelogram is defined in class to be a 
quadrilateral with 4 sides. 


Other comments:
Gerally 1-4 was good. Only 2 people lost points on it I think. However there 
was major overkill on it by a few people. 
1-6 was ok but people kept forgetting to prove both directions of the 
inequality 
1-7 was overall ok but I wasn't happy with a lot of the people's arguments 
for the points being planar 
1-9 This was generally ok but I got a couple of bizzare answers for proving 
4 points in R2 are planar.