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May 23, 2016 at 19:43 comment added amd Are you working with column vectors, in which case you left-multiply by the matrix, or with row vectors, in which case you right-multiply? It makes a difference, and unfortunately I can’t tell from $B$ since that’s symmetric.
May 23, 2016 at 17:15 vote accept Granger Obliviate
May 23, 2016 at 17:15 comment added Tim Huijgens The idea is that in an other basis we want a matrix $C$ which represents the same transformation as the matrix $A$ represents in the old basis. This can only be the case if $C$ maps all vectors in $\mathbb{R^3}$ to the same images as $A$. Therefore write down the image of $x$, this represents all images from $A$. Then write this down in the new basis-form, with new coördinates, calling it $y$. Finally we solve $Cx=y$ and we get $B$. If all works out correctly your answer should be $BAB^{-1}$. en.wikipedia.org/wiki/Change_of_basis
May 23, 2016 at 17:11 answer added windircurse timeline score: 0
May 23, 2016 at 17:05 comment added Granger Obliviate How is that going to help me @Tim Huijgens? I'm sorry I'm really feeling blank with this I need a more clear explanation... I'm not getting there alone
May 23, 2016 at 16:59 comment added Tim Huijgens Maybe you can try to write down the image of a random vector in $\mathbb{R^3}$, say $x=(x_1,x_2,x_3)$. Then ask yourself how you can write this vector in the new basis, call this one $y$. And solve the linear system of equations $Ax=y$.
May 23, 2016 at 16:54 history asked Granger Obliviate CC BY-SA 3.0