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 | | http://functions.wolfram.com/01.24.16.0031.01 | 
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 | | Sech[a - I b] == (2 Cos[b] Cosh[a] + 2 I Sin[b] Sinh[a])/
  (Cos[2 b] + Cosh[2 a]) | 
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 | | Cell[BoxData[RowBox[List[RowBox[List["Sech", "[", RowBox[List["a", "-", RowBox[List["\[ImaginaryI]", " ", "b"]]]], "]"]], "\[Equal]", FractionBox[RowBox[List[RowBox[List["2", " ", RowBox[List["Cos", "[", "b", "]"]], " ", RowBox[List["Cosh", "[", "a", "]"]]]], "+", RowBox[List["2", " ", "\[ImaginaryI]", " ", RowBox[List["Sin", "[", "b", "]"]], " ", RowBox[List["Sinh", "[", "a", "]"]]]]]], RowBox[List[RowBox[List["Cos", "[", RowBox[List["2", " ", "b"]], "]"]], "+", RowBox[List["Cosh", "[", RowBox[List["2", " ", "a"]], "]"]]]]]]]]] | 
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   <math xmlns='http://www.w3.org/1998/Math/MathML' mathematica:form='TraditionalForm' xmlns:mathematica='http://www.wolfram.com/XML/'>  <semantics>  <mrow>  <mrow>  <mi> sech </mi>  <mo> ⁡ </mo>  <mo> ( </mo>  <mrow>  <mi> a </mi>  <mo> - </mo>  <mrow>  <mi> ⅈ </mi>  <mo> ⁢ </mo>  <mi> b </mi>  </mrow>  </mrow>  <mo> ) </mo>  </mrow>  <mo> ⩵ </mo>  <mfrac>  <mrow>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mrow>  <mi> cos </mi>  <mo> ⁡ </mo>  <mo> ( </mo>  <mi> b </mi>  <mo> ) </mo>  </mrow>  <mo> ⁢ </mo>  <mrow>  <mi> cosh </mi>  <mo> ⁡ </mo>  <mo> ( </mo>  <mi> a </mi>  <mo> ) </mo>  </mrow>  </mrow>  <mo> + </mo>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mi> ⅈ </mi>  <mo> ⁢ </mo>  <mrow>  <mi> sin </mi>  <mo> ⁡ </mo>  <mo> ( </mo>  <mi> b </mi>  <mo> ) </mo>  </mrow>  <mo> ⁢ </mo>  <mrow>  <mi> sinh </mi>  <mo> ⁡ </mo>  <mo> ( </mo>  <mi> a </mi>  <mo> ) </mo>  </mrow>  </mrow>  </mrow>  <mrow>  <mrow>  <mi> cos </mi>  <mo> ⁡ </mo>  <mo> ( </mo>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mi> b </mi>  </mrow>  <mo> ) </mo>  </mrow>  <mo> + </mo>  <mrow>  <mi> cosh </mi>  <mo> ⁡ </mo>  <mo> ( </mo>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mi> a </mi>  </mrow>  <mo> ) </mo>  </mrow>  </mrow>  </mfrac>  </mrow>  <annotation-xml encoding='MathML-Content'>  <apply>  <eq />  <apply>  <sech />  <apply>  <plus />  <ci> a </ci>  <apply>  <times />  <cn type='integer'> -1 </cn>  <apply>  <times />  <imaginaryi />  <ci> b </ci>  </apply>  </apply>  </apply>  </apply>  <apply>  <times />  <apply>  <plus />  <apply>  <times />  <cn type='integer'> 2 </cn>  <apply>  <cos />  <ci> b </ci>  </apply>  <apply>  <cosh />  <ci> a </ci>  </apply>  </apply>  <apply>  <times />  <cn type='integer'> 2 </cn>  <imaginaryi />  <apply>  <sin />  <ci> b </ci>  </apply>  <apply>  <sinh />  <ci> a </ci>  </apply>  </apply>  </apply>  <apply>  <power />  <apply>  <plus />  <apply>  <cos />  <apply>  <times />  <cn type='integer'> 2 </cn>  <ci> b </ci>  </apply>  </apply>  <apply>  <cosh />  <apply>  <times />  <cn type='integer'> 2 </cn>  <ci> a </ci>  </apply>  </apply>  </apply>  <cn type='integer'> -1 </cn>  </apply>  </apply>  </apply>  </annotation-xml>  </semantics>  </math> 
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 | | Cell[BoxData[RowBox[List[RowBox[List["HoldPattern", "[", RowBox[List["Sech", "[", RowBox[List["a_", "-", RowBox[List["\[ImaginaryI]", " ", "b_"]]]], "]"]], "]"]], "\[RuleDelayed]", FractionBox[RowBox[List[RowBox[List["2", " ", RowBox[List["Cos", "[", "b", "]"]], " ", RowBox[List["Cosh", "[", "a", "]"]]]], "+", RowBox[List["2", " ", "\[ImaginaryI]", " ", RowBox[List["Sin", "[", "b", "]"]], " ", RowBox[List["Sinh", "[", "a", "]"]]]]]], RowBox[List[RowBox[List["Cos", "[", RowBox[List["2", " ", "b"]], "]"]], "+", RowBox[List["Cosh", "[", RowBox[List["2", " ", "a"]], "]"]]]]]]]]] | 
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 | | Date Added to functions.wolfram.com (modification date) | 
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