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 | | http://functions.wolfram.com/01.21.27.0084.01 | 
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 | | ArcTanh[Tanh[z]] == Piecewise[
  {{Indeterminate, Element[(-2 I z + Pi)/(2 Pi), Integers]}, 
   {z - Pi I Floor[(2 Im[z] - Pi)/(2 Pi)], 
    Element[(2 Im[z] + Pi)/(2 Pi), Integers] && Re[z] < 0}, 
   {z - Pi I Floor[(2 Im[z] + Pi)/(2 Pi)], True}}] | 
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 | | Cell[BoxData[RowBox[List[RowBox[List["ArcTanh", "[", RowBox[List["Tanh", "[", "z", "]"]], "]"]], "\[Equal]", RowBox[List["Piecewise", "[", RowBox[List["{", RowBox[List[RowBox[List["{", RowBox[List["Indeterminate", ",", RowBox[List[FractionBox[RowBox[List[RowBox[List[RowBox[List["-", "2"]], "\[ImaginaryI]", " ", "z"]], "+", "\[Pi]"]], RowBox[List["2", "\[Pi]"]]], "\[Element]", "Integers"]]]], "}"]], ",", RowBox[List["{", RowBox[List[RowBox[List["z", "-", RowBox[List["\[Pi]", " ", "\[ImaginaryI]", " ", RowBox[List["Floor", "[", FractionBox[RowBox[List[RowBox[List["2", RowBox[List["Im", "[", "z", "]"]]]], "-", "\[Pi]"]], RowBox[List["2", "\[Pi]"]]], "]"]]]]]], ",", RowBox[List[RowBox[List[FractionBox[RowBox[List[RowBox[List["2", RowBox[List["Im", "[", "z", "]"]]]], "+", "\[Pi]"]], RowBox[List["2", "\[Pi]"]]], "\[Element]", "Integers"]], "\[And]", RowBox[List[RowBox[List["Re", "[", "z", "]"]], "<", "0"]]]]]], "}"]], ",", "\[IndentingNewLine]", RowBox[List["{", RowBox[List[RowBox[List["z", "-", RowBox[List["\[Pi]", " ", "\[ImaginaryI]", " ", RowBox[List["Floor", "[", FractionBox[RowBox[List[RowBox[List["2", RowBox[List["Im", "[", "z", "]"]]]], "+", "\[Pi]"]], RowBox[List["2", "\[Pi]"]]], "]"]]]]]], ",", "True"]], "}"]]]], "}"]], "]"]]]]]] | 
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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>  <msup>  <mi> tanh </mi>  <mrow>  <mo> - </mo>  <mn> 1 </mn>  </mrow>  </msup>  <mo> ( </mo>  <mrow>  <mi> tanh </mi>  <mo> ⁡ </mo>  <mo> ( </mo>  <mi> z </mi>  <mo> ) </mo>  </mrow>  <mo> ) </mo>  </mrow>  <mo>  </mo>  <mrow>  <mo>  </mo>  <mtable>  <mtr>  <mtd>  <mi> ¿ </mi>  </mtd>  <mtd>  <mrow>  <mfrac>  <mrow>  <mi> π </mi>  <mo> - </mo>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mi> ⅈ </mi>  <mo> ⁢ </mo>  <mi> z </mi>  </mrow>  </mrow>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mi> π </mi>  </mrow>  </mfrac>  <mo> ∈ </mo>  <semantics>  <mi> ℤ </mi>  <annotation encoding='Mathematica'> TagBox["\[DoubleStruckCapitalZ]", Function[List[], Integers]] </annotation>  </semantics>  </mrow>  </mtd>  </mtr>  <mtr>  <mtd>  <mrow>  <mi> z </mi>  <mo> - </mo>  <mrow>  <mi> π </mi>  <mo> ⁢ </mo>  <mi> ⅈ </mi>  <mo> ⁢ </mo>  <mrow>  <mo> ⌊ </mo>  <mfrac>  <mrow>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mrow>  <mi> Im </mi>  <mo> ⁡ </mo>  <mo> ( </mo>  <mi> z </mi>  <mo> ) </mo>  </mrow>  </mrow>  <mo> - </mo>  <mi> π </mi>  </mrow>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mi> π </mi>  </mrow>  </mfrac>  <mo> ⌋ </mo>  </mrow>  </mrow>  </mrow>  </mtd>  <mtd>  <mrow>  <mrow>  <mfrac>  <mrow>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mrow>  <mi> Im </mi>  <mo> ⁡ </mo>  <mo> ( </mo>  <mi> z </mi>  <mo> ) </mo>  </mrow>  </mrow>  <mo> + </mo>  <mi> π </mi>  </mrow>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mi> π </mi>  </mrow>  </mfrac>  <mo> ∈ </mo>  <semantics>  <mi> ℤ </mi>  <annotation encoding='Mathematica'> TagBox["\[DoubleStruckCapitalZ]", Function[List[], Integers]] </annotation>  </semantics>  </mrow>  <mo> ∧ </mo>  <mrow>  <mrow>  <mi> Re </mi>  <mo> ⁡ </mo>  <mo> ( </mo>  <mi> z </mi>  <mo> ) </mo>  </mrow>  <mo> < </mo>  <mn> 0 </mn>  </mrow>  </mrow>  </mtd>  </mtr>  <mtr>  <mtd>  <mrow>  <mi> z </mi>  <mo> - </mo>  <mrow>  <mi> π </mi>  <mo> ⁢ </mo>  <mi> ⅈ </mi>  <mo> ⁢ </mo>  <mrow>  <mo> ⌊ </mo>  <mfrac>  <mrow>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mrow>  <mi> Im </mi>  <mo> ⁡ </mo>  <mo> ( </mo>  <mi> z </mi>  <mo> ) </mo>  </mrow>  </mrow>  <mo> + </mo>  <mi> π </mi>  </mrow>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mi> π </mi>  </mrow>  </mfrac>  <mo> ⌋ </mo>  </mrow>  </mrow>  </mrow>  </mtd>  <mtd>  <mi> True </mi>  </mtd>  </mtr>  </mtable>  </mrow>  </mrow>  <annotation-xml encoding='MathML-Content'>  <apply>  <eq />  <apply>  <arctanh />  <apply>  <tanh />  <ci> z </ci>  </apply>  </apply>  <apply>  <ci> Piecewise </ci>  <list>  <list>  <ci> ¿ </ci>  <apply>  <in />  <apply>  <times />  <apply>  <plus />  <pi />  <apply>  <times />  <cn type='integer'> -1 </cn>  <apply>  <times />  <cn type='integer'> 2 </cn>  <imaginaryi />  <ci> z </ci>  </apply>  </apply>  </apply>  <apply>  <power />  <apply>  <times />  <cn type='integer'> 2 </cn>  <pi />  </apply>  <cn type='integer'> -1 </cn>  </apply>  </apply>  <integers />  </apply>  </list>  <list>  <apply>  <plus />  <ci> z </ci>  <apply>  <times />  <cn type='integer'> -1 </cn>  <apply>  <times />  <pi />  <imaginaryi />  <apply>  <floor />  <apply>  <times />  <apply>  <plus />  <apply>  <times />  <cn type='integer'> 2 </cn>  <apply>  <imaginary />  <ci> z </ci>  </apply>  </apply>  <apply>  <times />  <cn type='integer'> -1 </cn>  <pi />  </apply>  </apply>  <apply>  <power />  <apply>  <times />  <cn type='integer'> 2 </cn>  <pi />  </apply>  <cn type='integer'> -1 </cn>  </apply>  </apply>  </apply>  </apply>  </apply>  </apply>  <apply>  <and />  <apply>  <in />  <apply>  <times />  <apply>  <plus />  <apply>  <times />  <cn type='integer'> 2 </cn>  <apply>  <imaginary />  <ci> z </ci>  </apply>  </apply>  <pi />  </apply>  <apply>  <power />  <apply>  <times />  <cn type='integer'> 2 </cn>  <pi />  </apply>  <cn type='integer'> -1 </cn>  </apply>  </apply>  <integers />  </apply>  <apply>  <lt />  <apply>  <real />  <ci> z </ci>  </apply>  <cn type='integer'> 0 </cn>  </apply>  </apply>  </list>  <list>  <apply>  <plus />  <ci> z </ci>  <apply>  <times />  <cn type='integer'> -1 </cn>  <apply>  <times />  <pi />  <imaginaryi />  <apply>  <floor />  <apply>  <times />  <apply>  <plus />  <apply>  <times />  <cn type='integer'> 2 </cn>  <apply>  <imaginary />  <ci> z </ci>  </apply>  </apply>  <pi />  </apply>  <apply>  <power />  <apply>  <times />  <cn type='integer'> 2 </cn>  <pi />  </apply>  <cn type='integer'> -1 </cn>  </apply>  </apply>  </apply>  </apply>  </apply>  </apply>  <true />  </list>  </list>  </apply>  </apply>  </annotation-xml>  </semantics>  </math> 
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 | | Cell[BoxData[RowBox[List[RowBox[List["HoldPattern", "[", RowBox[List["ArcTanh", "[", RowBox[List["Tanh", "[", "z_", "]"]], "]"]], "]"]], "\[RuleDelayed]", RowBox[List["\[Piecewise]", GridBox[List[List["Indeterminate", RowBox[List[FractionBox[RowBox[List[RowBox[List[RowBox[List["-", "2"]], " ", "\[ImaginaryI]", " ", "z"]], "+", "\[Pi]"]], RowBox[List["2", " ", "\[Pi]"]]], "\[Element]", "Integers"]]], List[RowBox[List["z", "-", RowBox[List["\[Pi]", " ", "\[ImaginaryI]", " ", RowBox[List["Floor", "[", FractionBox[RowBox[List[RowBox[List["2", " ", RowBox[List["Im", "[", "z", "]"]]]], "-", "\[Pi]"]], RowBox[List["2", " ", "\[Pi]"]]], "]"]]]]]], RowBox[List[RowBox[List[FractionBox[RowBox[List[RowBox[List["2", " ", RowBox[List["Im", "[", "z", "]"]]]], "+", "\[Pi]"]], RowBox[List["2", " ", "\[Pi]"]]], "\[Element]", "Integers"]], "&&", RowBox[List[RowBox[List["Re", "[", "z", "]"]], "<", "0"]]]]], List[RowBox[List["z", "-", RowBox[List["\[Pi]", " ", "\[ImaginaryI]", " ", RowBox[List["Floor", "[", FractionBox[RowBox[List[RowBox[List["2", " ", RowBox[List["Im", "[", "z", "]"]]]], "+", "\[Pi]"]], RowBox[List["2", " ", "\[Pi]"]]], "]"]]]]]], "True"]], Rule[ColumnAlignments, List[Left]], Rule[ColumnSpacings, 1.2`], Rule[ColumnWidths, Automatic]]]]]]]] | 
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 | | Date Added to functions.wolfram.com (modification date) | 
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