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<div><span class="kw">theorem </span><a NAME="T79"><span class="comment"><font color="firebrick">:: SIN_COS9:79</font></span><br/></a><div class="add"> <a href="relset_1.html#K1" title="RELSET_1:func.1">dom</a> <a href="sin_cos9.html#K1" title="SIN_COS9:func.1">arctan</a> is  <a href="rcomp_1.html#V3" title="RCOMP_1:attr.3">open</a> </div></div>
