如何将这个矩阵乘以 matlab

Question

so we have this matrix a=[1;2;3] and we want to multiply it by itself a*a ,

However Matlab doesn't do this multiplicaiton, and suggests using a.^2 , but this only multiplies each member by itself ( 1;4;9 ) ...

so how to multiply in Matlab a*a (a^2) ??

Greeed

Answer 1

You can't multiply it by itself, because it's not square.

You can multiply it by its transpose, though:

a * a'

or:

a' * a

Which one you use depends on what you want. But it sounds like you don't know what you want (otherwise there would be no question...)

Answer 2

you can't multiply this two matrices, see why here:

In your case it is 3X1 matrix multiply by 3X1 matrix.

http://en.wikipedia.org/wiki/Matrix_multiplication#Illustration