332 CHAPTER 13. MATRICES AND THE INNER PRODUCT
60. Show that A+ = (A∗A)+ A∗. Hint: You might use the description of A+ in terms ofthe singular value decomposition.
61. Let A =
(1 −3 03 −1 0
). Then
−√
2/2√
2/2 0√2/2
√2/2 0
0 0 1
T
AT A
−√
2/2√
2/2 0√2/2
√2/2 0
0 0 1
=
16 0 00 4 00 0 0
AAT =
(10 66 10
). A matrix U with
UT AATU =
(16 00 4
)
is
( √2/2 −
√2/2√
2/2√
2/2
). However,
( √2/2 −
√2/2√
2/2√
2/2
)T (1 −3 03 −1 0
) −√
2/2√
2/2 0√2/2
√2/2 0
0 0 1
=
(−4 0 00 2 0
).
How can this be fixed so that you get
(4 0 00 2 0
)?