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ExpIntegralEi






Mathematica Notation

Traditional Notation









Gamma, Beta, Erf > ExpIntegralEi[z] > Complex characteristics > Signum value





http://functions.wolfram.com/06.35.19.0012.01









  


  










Input Form





Sign[ExpIntegralEi[x + I y]] == (ExpIntegralEi[x - x Sqrt[-(y^2/x^2)]] + ExpIntegralEi[x + x Sqrt[-(y^2/x^2)]] + I (x/y) Sqrt[-(y^2/x^2)] (ExpIntegralEi[x - x Sqrt[-(y^2/x^2)]] - ExpIntegralEi[ x + x Sqrt[-(y^2/x^2)]]))/ (2 Sqrt[ExpIntegralEi[x - x Sqrt[-(y^2/x^2)]] ExpIntegralEi[x + x Sqrt[-(y^2/x^2)]]])










Standard Form





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MathML Form







<math xmlns='http://www.w3.org/1998/Math/MathML' mathematica:form='TraditionalForm' xmlns:mathematica='http://www.wolfram.com/XML/'> <semantics> <mrow> <mrow> <mi> sgn </mi> <mo> &#8289; </mo> <mo> ( </mo> <mrow> <mi> Ei </mi> <mo> &#8289; </mo> <mo> ( </mo> <mrow> <mi> x </mi> <mo> + </mo> <mrow> <mi> &#8520; </mi> <mo> &#8290; </mo> <mi> y </mi> </mrow> </mrow> <mo> ) </mo> </mrow> <mo> ) </mo> </mrow> <mo> &#10869; </mo> <mrow> <mrow> <mo> ( </mo> <mrow> <mrow> <mfrac> <mrow> <mi> &#8520; </mi> <mtext> </mtext> </mrow> <mi> y </mi> </mfrac> <mo> &#8290; </mo> <msqrt> <mrow> <mo> - </mo> <mfrac> <msup> <mi> y </mi> <mn> 2 </mn> </msup> <msup> <mi> x </mi> <mn> 2 </mn> </msup> </mfrac> </mrow> </msqrt> <mo> &#8290; </mo> <mi> x </mi> <mo> &#8290; </mo> <mrow> <mo> ( </mo> <mrow> <mrow> <mi> Ei </mi> <mo> &#8289; </mo> <mo> ( </mo> <mrow> <mi> x </mi> <mo> - </mo> <mrow> <mi> x </mi> <mo> &#8290; </mo> <msqrt> <mrow> <mo> - </mo> <mfrac> <msup> <mi> y </mi> <mn> 2 </mn> </msup> <msup> <mi> x </mi> <mn> 2 </mn> </msup> </mfrac> </mrow> </msqrt> </mrow> </mrow> <mo> ) </mo> </mrow> <mo> - </mo> <mrow> <mi> Ei </mi> <mo> &#8289; 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Rule Form





Cell[BoxData[RowBox[List[RowBox[List["HoldPattern", "[", RowBox[List["Sign", "[", RowBox[List["ExpIntegralEi", "[", RowBox[List["x_", "+", RowBox[List["\[ImaginaryI]", " ", "y_"]]]], "]"]], "]"]], "]"]], "\[RuleDelayed]", FractionBox[RowBox[List[RowBox[List["ExpIntegralEi", "[", RowBox[List["x", "-", RowBox[List["x", " ", SqrtBox[RowBox[List["-", FractionBox[SuperscriptBox["y", "2"], SuperscriptBox["x", "2"]]]]]]]]], "]"]], "+", RowBox[List["ExpIntegralEi", "[", RowBox[List["x", "+", RowBox[List["x", " ", SqrtBox[RowBox[List["-", FractionBox[SuperscriptBox["y", "2"], SuperscriptBox["x", "2"]]]]]]]]], "]"]], "+", FractionBox[RowBox[List["\[ImaginaryI]", " ", "x", " ", SqrtBox[RowBox[List["-", FractionBox[SuperscriptBox["y", "2"], SuperscriptBox["x", "2"]]]]], " ", RowBox[List["(", RowBox[List[RowBox[List["ExpIntegralEi", "[", RowBox[List["x", "-", RowBox[List["x", " ", SqrtBox[RowBox[List["-", FractionBox[SuperscriptBox["y", "2"], SuperscriptBox["x", "2"]]]]]]]]], "]"]], "-", RowBox[List["ExpIntegralEi", "[", RowBox[List["x", "+", RowBox[List["x", " ", SqrtBox[RowBox[List["-", FractionBox[SuperscriptBox["y", "2"], SuperscriptBox["x", "2"]]]]]]]]], "]"]]]], ")"]]]], "y"]]], RowBox[List["2", " ", SqrtBox[RowBox[List[RowBox[List["ExpIntegralEi", "[", RowBox[List["x", "-", RowBox[List["x", " ", SqrtBox[RowBox[List["-", FractionBox[SuperscriptBox["y", "2"], SuperscriptBox["x", "2"]]]]]]]]], "]"]], " ", RowBox[List["ExpIntegralEi", "[", RowBox[List["x", "+", RowBox[List["x", " ", SqrtBox[RowBox[List["-", FractionBox[SuperscriptBox["y", "2"], SuperscriptBox["x", "2"]]]]]]]]], "]"]]]]]]]]]]]]










Date Added to functions.wolfram.com (modification date)





2007-05-02





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