3.24.2 Greatest hits from previous weeks

3.24.2.1 Can Mathematica do symbolic linear algebra?

http://mathematica.stackexchange.com/questions/3242/can-mathematica-do-symbolic-linear-algebra

 
For instance, is there some way I can say "let A and B be arbitrary real $m\times n$ and $k\times m$ matrices, Simplify[Transpose[Transpose[A].Transpose[B]]]" and Mathematica would simplify it to B.A? 
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- asked by nikie (38 votes), answered by helen (19 votes)

3.24.2.2 Calculate the 2D Fourier transform of an Image

http://mathematica.stackexchange.com/questions/29203/calculate-the-2d-fourier-transform-of-an-image

 
I am new to Mathematica, and using version 8.0. 
 
I would like to calculate the 2D Fourier Transform of an Image with Mathematica and plot the magnitude and phase spectrum, as well as reconstruct the  ...
 

- asked by user8727 (5 votes), answered by Nasser (27 votes)