Define three large matrices, say A in R

$2$

$10$

$\backslash$times $2$

$16$

$,$B in R

$2$

$16$

$\backslash$times $2$

$5$

$,$C in R

$2$

$5$

$\backslash$times $2$

$16$

$.$ Is there any difference in speed depending on whether you compute AB or AC

$$

$?$ Why? What changes if you initialize C$=$B

T

without copying memory? Why?