Question

i need help figuring this out use matrices abc and d to find each scalar product and sum or difference if possible if a operation is not defined lable it undefined

Answer 1

a=( 6 1 0 8/-4 3 7 11) b=(1 3/ -2 4) c=(-2 1/ 4 0/2 2/1 1) d=(5 -2/ 3 6)

Answer 2

12. b-2a

Answer 3

\[a=\left[\begin{matrix}6 & 1 &0 & 8 \\ -4 & 3 & 7 & 11\end{matrix}\right]\]\[b=\left[\begin{matrix}1 & 3 \\ -2 & 4\end{matrix}\right]\], right?

Answer 4

yes exactly

Answer 5

you can't do b-2a...

\[2a=\left[\begin{matrix}12 & 2 & 0 & 16 \\ -8 & 6 & 14 & 22\end{matrix}\right]\]but its dimension is 2x4...
b has dimension 2x2.

can't add/subtract matrices of differeing dimension

Answer 6

so it would be undefined?

Answer 7

thank you and if you dont mind i have 4 more similar to this one if you would like to help me i would greatly apreciate it

Answer 8

what do you think?

add/subtaction of matrices is defined by adding/subtracting corresponding entries.
if the matrices have differing dimensions, they won't have all corresponding entries.

Answer 9

fire away

Answer 10

i think its undefined because you cant solve itand thank you

Answer 11

13.AB
14.BA
15.AC-BD
16.4B-3D

Answer 12

do you know matrix arithmetic at all?

Answer 13

not really

Answer 14

sorry

Answer 15

i suggest you check out these sites and come back here if you have remaining questions.

http://www.purplemath.com/modules/mtrxadd.htm

http://www.purplemath.com/modules/mtrxmult.htm

Answer 16

ok thank you

Answer 17

@pgpilot326 i have a question the site for multiplication says multiply each row by the colums so in my case of AB i would do 6*1 6*2 and so on?

Answer 18

nvmi get it now

Answer 19

remember, to do multiplication of matrices, the number of columns of the left matrix must equal the number of rows for the right matrix.

so for AB we have A(2,4) or A has dimension 2x4 meaning A has 2 rows and 4 columns. B(2,2) or B has dimension 2x2 (2 rows and 2 columns)

SInce A is on the left, and B is on the right, does the number of columns of A match the number of rows of B?

4 <> 2 so no. Thus, we cannot multiply B by A on the left, i.e., cannot do AB.

Answer 20

oh so i did jus did all this work for nun i thought i had it

Answer 21

.AB=(6*1=6+1*-2=-2+0*1=0+8*-2=-16) (6*3=18+1*4=4+0*3=0+8*4=32)
(-4*1=-4+3*-2=-6+7*1=7+11*-2=-22) (-4*3=-12+3*4=12+7*3=21+11*4=44)
(6+-2+0+-16) (18+4+0+32) /(-4+-6+7+-22) (-12+12+21+44)
(-12 54/-25 65)

Answer 22

@pgpilot326

Answer 23

BA=(1*6=6+3*1=3+1*0=0+3*8=24) (1*-4=-4+3*3=9+1*7=7+3*11)
(-2*6=-12+4*1=4+-2*0=0+4*8=32) (-2*-4=8+4*3=12+-2*7=-14+4*11=44)
(6+3+0+24) (-4+9+7+33) /(-12+4+0+32) (8+12+-14+44)
(33 45/24 45)