Errata: (the files were updated at the time indicated near the erratum)
 March 6: 5 PM by Ruvani Fonseka: Exam 2, TF problem 10, typo: A^{67} should
be A^{2}. Exam 1, TF problem 6, the answer is false: 2x2 matrix with 1 in the
bottom left entry and 0s everywhere else has zeros in the diagonal but rank 1.
 March 5: 8 PM by Lauren Luther: Exam 2, Problem 10, typo:
T e_{1} = e_{1} = [2, 1] not [1,2].
The explanation was otherwise correct.
 March 5: 6 PM by HannShyuin Yew: Exam 2, TF problem 12. The explanation was wrong.
 March 5: 7 AM by Arda Ayvaz: Exam 2, Problem 3a: (5,5,1) is the solution.
Problem 7, typo x+2 should be replaced by x_{2} in the solution.
 March 3: 3 PM by Nike Sun: Exam 1, TF 7: the explanation was incorrect
March 5: the answer is FALSE: The matrix with 1 in the lower side diagonal and 0
else is not included and has rank 2.
 March 3: 10 AM: Exam 1, TF 16: the problem had dealt with 2x2 matrices.
We changed I_{2} to I_{n} now to make it more general. The
answer and explanation is unchanged.
