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<B>ERF EXTENDED</B> _ _ _  _ _ _  _ _ _  _ _ _ <B>operator</B><P>
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The special function package supplies an extended support for the 

<A HREF=r37_0255.html>erf</A> operator which implements the <em>error function
</em> 
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defint(e**(-x**2),x,0,infinity) * 2/sqrt(pi) 
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. 
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syntax: </H3>
<em>erf</em>(&lt;expression&gt;) 
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examples: </H3>
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erf(-x); 

  - erf(x)


on rounded; 

erf(0.35); 

  0.379382053562

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