Last answered:

29 Jul 2020

Posted on:

16 Jul 2020

0

Matrix multiplication

In this quiz, the correct answer is "all of the above". But I don't understand how B is correct.   
1 answers ( 0 marked as helpful)
Instructor
Posted on:

29 Jul 2020

0
Hi Lisa,  to be honest with you, the phrasing on the question could be a bit more precise.  What is meant in b) is: You multiply two incompatible matrices.  Because of course, matrix multiplication of matrices A * B, requires A to have dimensions of (mxn) and B to be of size (nxm) for them to be compatible. This of course means that if m and n are not equal, the matrices are of different sizes, multiplying them however, requires no recycling. In addition, the answer in a) should read : You multiple a matrix by a vector, when the two are incompatible For instance, multiplying a mxn matrix by a nx1 vector requires no recycling. Thanks for asking the question and sorry for the confusion!   Best,  365 Eli

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