Assignment 11 - Due Thursday 11/20/2003
Comment on Assignment 10: for some reason I put a star by question 13 from Section 2.4, even though I think this is not such an appropriate exercise to hand in. I think this was a mistake. Please remove question 13 from last week's assignment.
Read: Hubbard and Hubbard Section 2.5 and maybe even 2.6.
Exercises (Due Thursday 11/20/2003):
Hand in only the exercises which have stars by them.
Section 2.5 (pages 221-224): 1, 2, 3, 4, 6, 6b*, 7, 8*, 9*, 10*, 13, 15*, 19, 20
Extra questions:
1. Construct a matrix with no zero entries whose echelon form is
.2. Extend each of the following lists of vectors to a basis of the whole space (I write row vectors instead of column vectors because they fit on lines better):
(i) (1,1,1). (ii) (1,2,3), (0,2,3). (iii)* (1,2,3,4), (1,1,1,1), (0,0,1,2).
3. Consider the vectors (1,2,3), (3,2,1), (1,0,–1), (–1,2,5).
(i) Find a subset of these vectors which is a basis for the space which they span, and which contains the first vector.
(ii)* Find a subset of these vectors which is a basis for the space which they span, and which contains the last vector.
4*. Let U be the subspace of 4-dimensional space which consists of the vectors (w,x,y,z) for which w + x + y + z = 0. Extend the vector (1, –1, 1, –1) to a basis of U.
5*. Let U and V be linear subspaces of 10-dimensional real space. Suppose that U is a subset of V and that dim U = dim V = 5. Prove that U = V.
Peter's Poppycock:
You will be relieved to read that Peter is plum out of comments this week, be they coherent or rambling. We do, however, have:
Julian's Joke:
Teacher: You seem to be having trouble with those Math questions.
Student: It's not the questions I'm having trouble with, it's the answers.