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<A NAME=Ei>

<TITLE>Ei</TITLE></A>
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<B>EI</B> _ _ _  _ _ _  _ _ _  _ _ _ <B>operator</B><P>
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The <em>Ei</em> operator returns the Exponential Integral function. 
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syntax: </H3>
<em>Ei</em>(&lt;expression&gt;) 
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examples: </H3>
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df(ei(x),x); 

   x
  e
  ---
  x


on rounded; 

Ei(0.35); 

  - 0.0894340019184

</TT></PRE><P>The numeric values for the operator <em>Ei</em> are computed via t
he 
power series representation, which limits the argument range. 
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