Scalar matrix. A scalar matrix is a special kind of diagonal matrix. It is a diagonal matrix with equal-valued elements along the diagonal. Two examples of a scalar matrix appear below.
A =
3 0
0 3
B =
5 0 0
0 5 0
0 0 5
These square matrices play a prominent role in the application of matrix algebra to real-world problems. For example, a scalar matrix called the identity matrix is critical to the solution of simultaneous linear equations. (We cover the identity matrix later in the tutorial.)
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