Final answer:
The command M(1,3) refers to the element in the first row and third column of the matrix M, which is the number 18.
Step-by-step explanation:
The command M(1,3) in a matrix refers to the element located at the first row and third column of matrix M. Given the matrix M = [5 6 18; 2 4 12; 90 3 2], we can locate the element in the first row and third column to find the answer.
If we visualize the matrix, it looks like this:
M = | 5 6 18 |
| 2 4 12 |
|90 3 2 |
From this representation, we can see that the element in the first row and third column is 18.