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 | | http://functions.wolfram.com/01.26.27.1370.01 | 
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 | | ArcCosh[Sqrt[1 - z^2]/Sqrt[-z^2]] == (-I) (Pi/2 - ArcSec[z]) /; 
 Im[z] < 0 || (Element[z, Reals] && z < -1) | 
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 | | Cell[BoxData[RowBox[List[RowBox[List[RowBox[List["ArcCosh", "[", FractionBox[SqrtBox[RowBox[List["1", "-", SuperscriptBox["z", "2"]]]], SqrtBox[RowBox[List["-", SuperscriptBox["z", "2"]]]]], "]"]], "\[Equal]", RowBox[List[RowBox[List["-", "\[ImaginaryI]"]], " ", RowBox[List["(", RowBox[List[FractionBox["\[Pi]", "2"], "-", RowBox[List["ArcSec", "[", "z", "]"]]]], ")"]]]]]], "/;", " ", RowBox[List[RowBox[List[RowBox[List["Im", "[", "z", "]"]], "<", "0"]], "\[Or]", RowBox[List["(", RowBox[List[RowBox[List["z", "\[Element]", "Reals"]], "\[And]", RowBox[List["z", "<", RowBox[List["-", "1"]]]]]], ")"]]]]]]]] | 
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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>  <mrow>  <msup>  <mi> cosh </mi>  <mrow>  <mo> - </mo>  <mn> 1 </mn>  </mrow>  </msup>  <mo> ( </mo>  <mfrac>  <msqrt>  <mrow>  <mn> 1 </mn>  <mo> - </mo>  <msup>  <mi> z </mi>  <mn> 2 </mn>  </msup>  </mrow>  </msqrt>  <msqrt>  <mrow>  <mo> - </mo>  <msup>  <mi> z </mi>  <mn> 2 </mn>  </msup>  </mrow>  </msqrt>  </mfrac>  <mo> ) </mo>  </mrow>  <mo> ⩵ </mo>  <mrow>  <mrow>  <mo> - </mo>  <mi> ⅈ </mi>  </mrow>  <mo> ⁢ </mo>  <mrow>  <mo> ( </mo>  <mrow>  <mfrac>  <mi> π </mi>  <mn> 2 </mn>  </mfrac>  <mo> - </mo>  <mrow>  <msup>  <mi> sec </mi>  <mrow>  <mo> - </mo>  <mn> 1 </mn>  </mrow>  </msup>  <mo> ( </mo>  <mi> z </mi>  <mo> ) </mo>  </mrow>  </mrow>  <mo> ) </mo>  </mrow>  </mrow>  </mrow>  <mo> /; </mo>  <mrow>  <mrow>  <mrow>  <mi> Im </mi>  <mo> ⁡ </mo>  <mo> ( </mo>  <mi> z </mi>  <mo> ) </mo>  </mrow>  <mo> < </mo>  <mn> 0 </mn>  </mrow>  <mo> ∨ </mo>  <mrow>  <mo> ( </mo>  <mrow>  <mrow>  <mi> z </mi>  <mo> ∈ </mo>  <mi> ℝ </mi>  </mrow>  <mo> ∧ </mo>  <mrow>  <mi> z </mi>  <mo> < </mo>  <mrow>  <mo> - </mo>  <mn> 1 </mn>  </mrow>  </mrow>  </mrow>  <mo> ) </mo>  </mrow>  </mrow>  </mrow>  <annotation-xml encoding='MathML-Content'>  <apply>  <ci> Condition </ci>  <apply>  <eq />  <apply>  <arccosh />  <apply>  <times />  <apply>  <power />  <apply>  <plus />  <cn type='integer'> 1 </cn>  <apply>  <times />  <cn type='integer'> -1 </cn>  <apply>  <power />  <ci> z </ci>  <cn type='integer'> 2 </cn>  </apply>  </apply>  </apply>  <cn type='rational'> 1 <sep /> 2 </cn>  </apply>  <apply>  <power />  <apply>  <power />  <apply>  <times />  <cn type='integer'> -1 </cn>  <apply>  <power />  <ci> z </ci>  <cn type='integer'> 2 </cn>  </apply>  </apply>  <cn type='rational'> 1 <sep /> 2 </cn>  </apply>  <cn type='integer'> -1 </cn>  </apply>  </apply>  </apply>  <apply>  <times />  <apply>  <times />  <cn type='integer'> -1 </cn>  <imaginaryi />  </apply>  <apply>  <plus />  <apply>  <times />  <pi />  <apply>  <power />  <cn type='integer'> 2 </cn>  <cn type='integer'> -1 </cn>  </apply>  </apply>  <apply>  <times />  <cn type='integer'> -1 </cn>  <apply>  <arcsec />  <ci> z </ci>  </apply>  </apply>  </apply>  </apply>  </apply>  <apply>  <or />  <apply>  <lt />  <apply>  <imaginary />  <ci> z </ci>  </apply>  <cn type='integer'> 0 </cn>  </apply>  <apply>  <and />  <apply>  <in />  <ci> z </ci>  <ci> ℝ </ci>  </apply>  <apply>  <lt />  <ci> z </ci>  <cn type='integer'> -1 </cn>  </apply>  </apply>  </apply>  </apply>  </annotation-xml>  </semantics>  </math> 
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 | | Cell[BoxData[RowBox[List[RowBox[List["HoldPattern", "[", RowBox[List["ArcCosh", "[", FractionBox[SqrtBox[RowBox[List["1", "-", SuperscriptBox["z_", "2"]]]], SqrtBox[RowBox[List["-", SuperscriptBox["z_", "2"]]]]], "]"]], "]"]], "\[RuleDelayed]", RowBox[List[RowBox[List[RowBox[List["-", "\[ImaginaryI]"]], " ", RowBox[List["(", RowBox[List[FractionBox["\[Pi]", "2"], "-", RowBox[List["ArcSec", "[", "z", "]"]]]], ")"]]]], "/;", RowBox[List[RowBox[List[RowBox[List["Im", "[", "z", "]"]], "<", "0"]], "||", RowBox[List["(", RowBox[List[RowBox[List["z", "\[Element]", "Reals"]], "&&", RowBox[List["z", "<", RowBox[List["-", "1"]]]]]], ")"]]]]]]]]]] | 
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 | | Date Added to functions.wolfram.com (modification date) | 
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