
<A NAME=CLEARRULES>

<TITLE>CLEARRULES</TITLE></A>
<b><a href=r37_idx.html>INDEX</a></b><p><p>



<B>CLEARRULES</B> _ _ _  _ _ _  _ _ _  _ _ _ <B>command</B><P>
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 <P>
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 <P> <H3> 
syntax: </H3>
<em>clearrules</em>&lt;list&gt;{,&lt;list&gt;}+ 
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The operator <em>clearrules</em> is used to remove previously defined 

<A HREF=r37_0060.html>rule</A> lists from the system. &lt;list&gt; can be an exp
licit rule 
list, or evaluate to a rule list. 
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<P>
 <P> <H3> 
examples: </H3>
<P><PRE><TT>
trig1 := {cos(~x)*cos(~y) =&gt; (cos(x+y)+cos(x-y))/2,
          cos(~x)*sin(~y) =&gt; (sin(x+y)-sin(x-y))/2,
          sin(~x)*sin(~y) =&gt; (cos(x-y)-cos(x+y))/2,
          cos(~x)^2       =&gt; (1+cos(2*x))/2,
          sin(~x)^2       =&gt; (1-cos(2*x))/2}$ 

let trig1;
cos(a)*cos(b); 

  COS(A - B) + COS(A + B)
  ----------------------- 
             2


clearrules trig1;
cos(a)*cos(b); 

  COS(A)*COS(B)

</TT></PRE><P>