matrix

A is an m x n array and B is an r x s array. how do i write an expression to multiply A and B and place the result in array C

Answer 1

[Junaid]

C = A * B;

Just make sure that dimensions of A and B are consistent to be multiplied as Suggested by Wayne King above.

Answer 2

[Wayne King]

If n and r are not equal, you can't. Unless there are some details that you are not telling us.

Answer 3

[Walter Roberson]

What size would you intend the result to be? Multiplication of matrices is defined if they are the same size, or if they are two dimensional (as yours are) and if the second dimension of one of them is the same as the first dimension of the other one (as yours are not)

[lowcalorie]

the same size as A and B just defined as matrix C

[Walter Roberson]

A and B are different sizes according to your "m x n and r x s". Are you looking for C to be m x s, or to be r x n, or to be m x n x r x s (4 dimensional), or to be m x n, or to be min(m,r) x min(n,s) or ... ?