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anonymous
 5 years ago
Can anyone prove y this identity wouldn't work for matrices
anonymous
 5 years ago
Can anyone prove y this identity wouldn't work for matrices

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anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0(a+b)(a+b)=a^2+2ab+b^2

JamesJ
 5 years ago
Best ResponseYou've already chosen the best response.3This identity is true if and only if AB = BA. So you need just one example of a pair of matrices A and B where that is not the case.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0problem is with the commutative law \[(a+b)(a+b)=a^2+ab+ba+b^2\]and .. . what jamesj said

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0ok Good but I think I need to use an arguement

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0I have to show by example and arguement

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0Do i shld just say abt commutative law ok?

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0a counter example is all you need. it is almost never the case that AB =BA

JamesJ
 5 years ago
Best ResponseYou've already chosen the best response.3Write down a pair of 2x2 matrices and see if commute. [ If you know anything about linear transformations, here are two that don't commute and you can see it geometrically:  A = rotation pi/2 anticlockwise  B = reflection in the xaxis ]
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