Question

et A and B be 2*2 matrices such that
2A+3B= 1 2
-1 -2
Atranspose +B transpose=-1 3
-7 6
Compute A and B

Answer 1

one sec I'll do it real quick

Answer 2

maybe not quickly

Answer 3

:D take ur time:)

Answer 4

ooooo right bad at addition, woops

Answer 5

u can attach a picture of ur paper with solution

Answer 6

check to see if these work correctly:
A = |-4 -23|
|16 -5|

Answer 7

B = |3 26|
|-7 8|

Answer 8

may u send me ur steps also

Answer 9

nono B = |3 16|
|-7 8|

Answer 10

umm it's fairly illegible

Answer 11

just attach a picture with ur steps and btw its perfectly right:)

Answer 12

the camera on my phone is pretty terrible, can't read my writing in pencil

Answer 13

steps I used: A^T + B^T = (A+B)^T thus:
a11 + b11 = -1
a22+ b22 = 6
a12 + b12 = -7
a21 + b21 = 3


and i solved for the a values and plugged them into the other set of equations

Answer 14

which are:
2a11 + 2b11 = 1
2a12 + 3b12 = 2
2a21 + 3b21 = -1
2a22+ 3b22 = -2

Answer 15

which gave me the values for B matrix then I plugged those values back into the first set of equations to get my A matrix

Answer 16

thanks alot:)

Answer 17

yep, matricies are fun!

Answer 18

wants alot of them?:D

Answer 19

hit me with another one, I'm tired of my linear algebra studying anyway

Answer 20

Let A be a 2*2 matrix Prove that if det(a)not equal zero then the inverse is given by A^-1=(1/det(A))adj(A)

Answer 21

check that alsoo s

Answer 22

hmm, i konw it has to do with the cofactor expansion, let me chew on that a sec

Answer 23

err, cofactor matrix

Answer 24

??

Answer 25

thinking on it, I should really know this.

Answer 26

ok :) take ur time

Answer 27

from cramer's rule we get:\[x_{j} = \det(A _{i}(e _{j})) / \det(A)\]
thus \[x _{ij} = (1/\det(A))C _{ji}\]
which gives us:\[A^{-1} = X = (1/\det(A))[C _{ji}] = (1/\det(A))[C _{ij}]^T\]

Answer 28

and \[[C _{ij}]^T = adj(A)\]

Answer 29

might need an Assume the \[\det(A) \ne 0\]

Answer 30

??

Answer 31

i pieced together a few statements, I'm pretty sure that is the right aproach but can't tell you how to do it exactly

Answer 32

and about the attachment did u check it? may u please check it:)

Answer 33

couldn't load it

Answer 34

http://en.wikipedia.org/wiki/Cramer's_rule

Answer 35

thanks:) i will send u the attachment again

Answer 36

you there?

Answer 37

yeah sorry lost the connection

Answer 38

thats the Gauss Jordan algorithm metod whats about the adjugates

Answer 39

are u there?

Answer 40

wouldn't let me type, look at both

Answer 41

perfect:)

Answer 42

want more?

Answer 43

sure

Answer 44

start a new thread though

Answer 45

ohh sorry ok:)