Send questions of potential general interest to math21b@fas.harvard.edu.

Question:In the first homework, there are relations in space which do not involve the z variable. Does this define an object in the plane?	Answer:
Question:No, in problem 1, all sets are sets in space. If you take for example the set x22 + z2 = 1, then the y variable is not involved. So, we can chose y arbitrarily. The equation defines a cylinder in space.	Answer: Is it ok to use an older edition of a textbook.

Please send questions and comments to maths21a@fas.harvard.edu

Maths21A | Oliver Knill | Summer 2008 | Summer school | Department of Mathematics | Faculty of Art and Sciences | Harvard University