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angela210793Best ResponseYou've already chosen the best response.4
dw:1328979083071:dw
 2 years ago

amistre64Best ResponseYou've already chosen the best response.4
cofactor, transpose, divide by determinant
 2 years ago

amistre64Best ResponseYou've already chosen the best response.4
or swap some stuff in a 2x2
 2 years ago

angela210793Best ResponseYou've already chosen the best response.4
let me try it and u tell me if i have solved it right ok???
 2 years ago

satellite73Best ResponseYou've already chosen the best response.0
yeah easy method for 2 by 2
 2 years ago

amistre64Best ResponseYou've already chosen the best response.4
forgot to transpose lol
 2 years ago

amistre64Best ResponseYou've already chosen the best response.4
last time .... and i forgot to use the checkerboard + correctly a b c d cofactors to: d c b a transposes to d c b a then divide by determinate maybe!! lol
 2 years ago

angela210793Best ResponseYou've already chosen the best response.4
is this right? dw:1328979427660:dw
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.0
for invertible 2x2 matrices\[A=\left[\begin{matrix}a & b \\ c & d\end{matrix}\right]\]\[A^{1}=\frac1{\det A}\left[\begin{matrix}d & b \\ c & a\end{matrix}\right]\]looks good angela
 2 years ago

FoolForMathBest ResponseYou've already chosen the best response.0
Trick: Swap the diagonal element and change the sign of offdiagonal ones
 2 years ago

amistre64Best ResponseYou've already chosen the best response.4
thats what i was trying for lol
 2 years ago

angela210793Best ResponseYou've already chosen the best response.4
I think cofactors will be d b c a
 2 years ago

amistre64Best ResponseYou've already chosen the best response.4
b is not its own cofactor
 2 years ago

FoolForMathBest ResponseYou've already chosen the best response.0
2 days back I learned a super fast way for doing 3x3 matrices
 2 years ago

amistre64Best ResponseYou've already chosen the best response.4
cofactor is the determinate of the submatrix
 2 years ago

amistre64Best ResponseYou've already chosen the best response.4
the submatrix of b is c in this case
 2 years ago

angela210793Best ResponseYou've already chosen the best response.4
Thanks guys :) How abt a 4x4 matrix????
 2 years ago

satellite73Best ResponseYou've already chosen the best response.0
\[ M = \left[ {\begin{array}{cc} x & y \\ z & w \\ \end{array} } \right] \] M = \begin{array}{cc} x & y \\ z & w \\ \end{array} \] \[ M^{1}= \frac{1}{xwyz}\left[ {\begin{array}{cc} w& y \\ z & x \\ \end{array} } \right] \]
 2 years ago

FoolForMathBest ResponseYou've already chosen the best response.0
For this one the answer is\[ \begin{bmatrix} \cos x & \sin x \\ \sin x & \cos x \end{bmatrix} \]
 2 years ago

amistre64Best ResponseYou've already chosen the best response.4
same process just messier and more apt to computers
 2 years ago

satellite73Best ResponseYou've already chosen the best response.0
god it took me a long time to write that
 2 years ago

angela210793Best ResponseYou've already chosen the best response.4
well am not a computer....O.o
 2 years ago

amistre64Best ResponseYou've already chosen the best response.4
then youll have to get a monk
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.0
Cofactors is a good way to get bigger determinants if the matrix has some number of zeros in it
 2 years ago

satellite73Best ResponseYou've already chosen the best response.0
finding inverse of 4 by 4 by hand is long process, use a machine
 2 years ago

FoolForMathBest ResponseYou've already chosen the best response.0
I like to use reduce rowechelon for method for 4x4
 2 years ago

satellite73Best ResponseYou've already chosen the best response.0
i like to use maple
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.0
if it's like 0022 1536 0739 0297 you can expand the cofactors along the first column and you only need to take one determinant, all the minors are zero except for 1
 2 years ago

angela210793Best ResponseYou've already chosen the best response.4
ahhhhaaaa...I got it.....Thank you all ^^
 2 years ago

amistre64Best ResponseYou've already chosen the best response.4
a b c d e f g h i j k l m n o p +fgh  egh +efh efg jkl ikl ijl ijk nop mop mnp mno etc ........... then transpose; and divide off the original determinate
 2 years ago

angela210793Best ResponseYou've already chosen the best response.4
Amistre u lost me....wht did u do in there??
 2 years ago

amistre64Best ResponseYou've already chosen the best response.4
the cofactor is the determinants of the submatrixes
 2 years ago

angela210793Best ResponseYou've already chosen the best response.4
I'm sorry but all i know for algorithms is the name....I have no idea wht they r
 2 years ago

amistre64Best ResponseYou've already chosen the best response.4
dw:1328980027433:dw
 2 years ago

angela210793Best ResponseYou've already chosen the best response.4
i know wht submatrices r...
 2 years ago

amistre64Best ResponseYou've already chosen the best response.4
an algorithm is a means of operating on data multiplication is an algorithm; division is an algorithm its a process that aids us
 2 years ago

amistre64Best ResponseYou've already chosen the best response.4
it sorts the data into a usable form that we can maniipulate to our own devious devices :)
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.0
yeah, all that procedural stuff the process you use in long division for example computers do all problems with algorithms, they never think 'outside the box' so to speak
 2 years ago

angela210793Best ResponseYou've already chosen the best response.4
OMG!!! I'm going to fail :(
 2 years ago

angela210793Best ResponseYou've already chosen the best response.4
cause i have to colve 100 probs and i have solved only 10...yay :P
 2 years ago

angela210793Best ResponseYou've already chosen the best response.4
and my stupid teacher doesn't know to explain at all _
 2 years ago

sasogeekBest ResponseYou've already chosen the best response.0
i know nothing about 4x4 matrices but i know there's something to do with +  + something somewhere dealing with cofactors and it should look something like this... not sure
 2 years ago

sasogeekBest ResponseYou've already chosen the best response.0
i think that's what amistre did when he drew "a" and wrote "sub" in the box
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.0
that will get you the determinant of a 4x4 if you want the inverse I would probably use the row reduction thing
 2 years ago

TuringTestBest ResponseYou've already chosen the best response.0
this is a good site http://tutorial.math.lamar.edu/Classes/LinAlg/FindingInverseMatrices.aspx
 2 years ago

sasogeekBest ResponseYou've already chosen the best response.0
Angela, you need to get it, u don't need to "kinda" get it... that won't get u far lol :P
 2 years ago

angela210793Best ResponseYou've already chosen the best response.4
Leave me alone geek...:P I got microeconomy,finance,communication to study too _
 2 years ago

sasogeekBest ResponseYou've already chosen the best response.0
welcome to university :)
 2 years ago

angela210793Best ResponseYou've already chosen the best response.4
yea right :'( I wish i never started it :P
 2 years ago

Akshay_BudhkarBest ResponseYou've already chosen the best response.0
i wish i start it soon! @angela
 2 years ago

angela210793Best ResponseYou've already chosen the best response.4
tht's cause u don't know yet wht it feels like to be in univ :p
 2 years ago

Akshay_BudhkarBest ResponseYou've already chosen the best response.0
if i dont go to univ i wont be great :P
 2 years ago

angela210793Best ResponseYou've already chosen the best response.4
u may go to univ and still not b great Akshay
 2 years ago

Akshay_BudhkarBest ResponseYou've already chosen the best response.0
i will be its a guarantee as it is "ME" :P
 2 years ago

Akshay_BudhkarBest ResponseYou've already chosen the best response.0
u got matrices in economics?
 2 years ago

angela210793Best ResponseYou've already chosen the best response.4
yea we have maths...and we're getting too much information in just one lecture..teacher never shows an example to us and we're all like: ''Is tht chinese??''
 2 years ago
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