<PRE><B>Question 182413</B>
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*[tex \LARGE \text{          }\math x &lt; 0 \ \ \Rightarrow\ \ ] &lt;i&gt;x&lt;/i&gt; is negative.


So, let &lt;i&gt;s&lt;/i&gt; be a positive number with the same magnitude as &lt;i&gt;x&lt;/i&gt;.  Then -&lt;i&gt;s&lt;/i&gt; = &lt;i&gt;x&lt;/i&gt;.


Multiply both sides of -&lt;i&gt;s&lt;/i&gt; = &lt;i&gt;x&lt;/i&gt; by -1: &lt;i&gt;s&lt;/i&gt; = -&lt;i&gt;x&lt;/i&gt;.


But since &lt;i&gt;s&lt;/i&gt; is positive, -&lt;i&gt;x&lt;/i&gt; must also be positive.







John
*[tex \LARGE e^{i\pi} + 1 = 0]
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