# Thread: multiplication of two matrix

1. ## multiplication of two matrix

A = | 1 2 |
3 4

b = | 1 3 |
5 7

a* b = ?

2. Hello, ranjitbd!

If you know how to multiply matrices, exactly where is your difficulty?
If you don't know how, this is not the place to learn it.

Gtiven: . $A \:=\:\begin{vmatrix} 1&2 \\ 3&4 \end{vmatrix} \qquad B \:=\:\begin{vmatrix}1&3\\5&7 \end{vmatrix}$

Find: . $A\cdot B$

$A\cdot B \;=\;\begin{vmatrix}1&2\\3&4\end{vmatrix}\, \begin{vmatrix}1&3\\5&7\end{vmatrix}$ . $= \;\begin{vmatrix}(1)(1)+(2)(5) & (1)(3)+(2)(7) \\ (3)(1)+(4)(5) & (3)(3)+(4)(7)\end{vmatrix} \;=\;\begin{vmatrix}11 & 17 \\ 23 & 37 \end{vmatrix}$

3. ## example of a matrix multiplication

give me an example

4. ## really thanks...

Originally Posted by ranjitbd
give me an example
i know but i have forgotten....just imagine i have completed my 12 standard on april 1999.
anyway wish u all the best