Part 12a: Symmetric Matrices
page 337 (section 6.4):   # 1, 5, 11, 12, 17.
    Comment:  #12 "from columns times rows of Q" means rewrite the expression as a matrix
               product of Q with Q^T where you give the columns/rows of Q.  Also, note
               that the zero at the end of the question is a matrix zero (not scalar).

Part 12b: Positive Definite Matrices
page 350 (section 6.5):   # 1, 7, 10, 11, 16, 28.
    Comment:  #10 As the notation suggests, use the energy formulation to show 
                  positive definite.  That is, don't find A or B.
Study for the exam by 
  1) reading the text and lecture notes, 
  2) doing problems from the list of good problems, 
  3) making an outline of the course so far and 
  4) creating example problems of your own for the exam.