Suppose That$\boldsymbol { A } , \boldsymbol { B }$

Question

Examlex · Accepted Answer

The Answer is To multiply

A

by

B

, we will need 3.4

5 = 60

multiplications. The result is a

3 imes 5

matrix. To multiply it by

C

will require

3 \cdot 5 \cdot 6 = 90

multiplications. This gives a total of

60 + 90 = 150

steps. On the other hand, if we multiply

\boldsymbol { B }

by

\boldsymbol { C }

first, we use

4 \cdot 5 \cdot 6 = 120

multiplications and then another

3 \cdot 4 \cdot 6 = 72

to multiply

\boldsymbol { A }

by the

4 imes 6

matrix

B C

. This method uses a total of

120 + 72 = 192

steps. Therefore the first method is a little faster.

Suppose That $\boldsymbol { A } , \boldsymbol { B }$