Final answer:
Two examples of non-zero 3x3 matrices a and b such that ab = 0 are provided. It is shown that ba is not necessarily equal to 0 and a^2 is not equal to the zero matrix.
Step-by-step explanation:
To find two non-zero 3x3 matrices a and b such that ab = 0, we can use the following examples:
Example 1:
a = [1 0 0; 0 0 0; 0 0 0]
b = [0 0 0; 1 0 0; 0 0 0]
Example 2:
a = [0 0 0; 0 1 0; 0 0 0]
b = [0 0 0; 0 0 0; 0 0 1]
In both examples, a multiplied by b equals the zero matrix. However, in Example 1, b multiplied by a is not equal to the zero matrix, while in Example 2, b multiplied by a is also equal to the zero matrix.
So, the answer to part A is no, ba is not equal to zero in both examples.
For part B, it is not always true that ba = 0. The examples provided demonstrate this.
In both examples, a^2 is not equal to the zero matrix.