MHB Matrix Transforms: nxm, n->m, m->n, n+m->n/m

Imiebee
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A matrix of dimension nxm
a. transforms a vector of dimension n to a vector of dimension m
b. transforms a vector of dimension m to a vector of dimension n
c. a vector of dimension n+m to a vector of dimension m
d. a vector of dimension n+m to a vector of dimension n
 
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Matrix multiplication (note that a vector is just an m x 1 matrix)

(n x m) X (m x k) => (n x k)

See if you can figure it out now.
 
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Imiebee said:
A matrix of dimension nxm
So which is the number of rows and which is the number of columns?

a. transforms a vector of dimension n to a vector of dimension m
b. transforms a vector of dimension m to a vector of dimension n
c. a vector of dimension n+m to a vector of dimension m
d. a vector of dimension n+m to a vector of dimension n
 
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