Question

Determine whether the non-homogeneous system Ax=b is consistent

Answer 1

god i hate linear algebra...

Answer 2

do you know what has to be true for it to be consistent?

Answer 3

Mee too

Answer 4

yes it must have 4 pivots

Answer 5

Now i am getting confused since the example shown in the book its not like that idk I am confused

Answer 6

usually i always just start by trying to get it into echelon form

Answer 7

oh this is what my book states:
It is consistent if and only if b is the column space of A

Answer 8

umm did u open that link?

Answer 9

that showed the matrix in row reduced form

Answer 10

so from my understanding, it is consistent if the system has at least one solution. in other words i would reduce the matrix to echelon form and then if you get a row that is say
[0 0 0 1] then that would mean 0 = 1 which means that it is not consistent. but if you get a row that is say [0 0 1 9] then that just means x3 = 9, therefore consistent

Answer 11

So wld u think that this system is consistent?

Answer 12

I would say nooooo

Answer 13

umm.. one sec

Answer 14

which #? 41?

Answer 15

oh whoops #42 umm I checked it row reduce form on wolfram and here is the link:
http://www.wolframalpha.com/input/?i=matrix&a=*C.matrix-_*Calculator.dflt-&a=FSelect_**MatrixOperations-.MatricesOperations-&a=*FP.MatrixOperations.matrixop-_rowreduce&f4= {{3%2C-8%2C4%2C0%2C19}%2C{0%2C-6%2C2%2C4%2C5}%2C{5%2C0%2C22%2C1%2C29}%2C{1%2C-2%2C2%2C0%2C8}}&f=MatrixOperations.theMatrix_{{3%2C-8%2C4%2C0%2C19}%2C{0%2C-6%2C2%2C4%2C5}%2C{5%2C0%2C22%2C1%2C29}%2C{1%2C-2%2C2%2C0%2C8}}

Answer 16

umm u r gonna have to copy and paste it since the link is misbehaving

Answer 17

ya so see the last line has 0 = 1 which means that it is incosistent

Answer 18

and awesome i didnt know you could do that in wolfram alpha. that is sure gonna make hw a lot simpler! thanks!

Answer 19

ok Thanks :DDD