If for any triangle ABC
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<br clear="all" /><table border="0" width="100%"><tr><td>
<table align="center"><tr><td nowrap="nowrap" align="center">
tan(<i>A</i> &#8722; <i>B</i>) + tan(<i>B</i> &#8722; <i>C</i>) + tan(<i>C</i> &#8722; <i>A</i>) = 0 </td></tr></table>
</td></tr></table>


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what can you say about the triangle?