Graphics Programs Reference
In-Depth Information
EXAMPLE A6
Evaluate the matrix product
AB
, where
A
is given in Example A4 and
⎡
⎣
⎤
⎦
−
4
1
B
=
1
−
4
2
−
2
Solution
⎡
⎣
⎤
⎦
a
1
·
b
1
a
1
·
b
2
AB
=
a
2
·
b
1
a
2
·
b
2
a
3
·
b
1
a
3
·
b
2
⎡
⎣
⎤
⎦ =
⎡
⎣
⎤
⎦
−
+
+
+
−
+
−
−
1(
4)
2(1)
3(2) 1(1)
2(
4)
3(
2)
4
13
=
1(
−
4)
+
2(1)
+
1(2) 1(1)
+
2(
−
4)
+
1(
−
2)
0
−
9
0(
−
4)
+
1(1)
+
2(2)0 1)
+
1(
−
4)
+
2(
−
2)
5
−
8