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      <text>7.2.3.4 Introducing the zero matrix</text>
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      <text><![CDATA[<h3> The zero matrix </h3>
<p>We call \(B=\begin{bmatrix}0 &amp; 0 \\ 0 &amp; 0 \end{bmatrix}\) the \(2 \times 2\) <b>zero matrix</b> written \(\underline{0}\) so that \(A \cdot \underline{0} = \underline{0} \cdot A = \underline{0}\) for any matrix \(A.\)</p>
<p>Now in the multiplication of numbers, the equation \(ab = 0\) implies that either \(a\) is zero or \(b\) is zero or both are zero. The following task shows that this is not necessarily true for matrices.</p>]]></text>
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