Preview Activity 2.2.1. Matrix operations.
(a)
(b)
(c)
Suppose that and are two matrices. What do we need to know about their shapes before we can form the sum
(d)
The matrix which we call the identity matrix, is the matrix whose entries are zero except for the diagonal entries, all of which are 1. For instance,
If we can form the sum what must be true about the matrix