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 | | http://functions.wolfram.com/07.15.19.0002.01 | 
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 | | Im[JacobiP[n, a, b, x + I y]] == 
  Sum[(((-1)^j Pochhammer[n + a + b + 1, 2 j + 1])/(2^(2 j + 1) (2 j + 1)!)) 
    JacobiP[n - 2 j - 1, a + 2 j + 1, b + 2 j + 1, x] y^(2 j + 1), 
   {j, 0, Floor[(n - 1)/2]}] /; Element[x, Reals] && Element[y, Reals] && 
  Element[a, Reals] && Element[b, Reals] && Element[n, Integers] && n >= 0 | 
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 | | Cell[BoxData[RowBox[List[RowBox[List[RowBox[List["Im", "[", RowBox[List["JacobiP", "[", RowBox[List["n", ",", "a", ",", "b", ",", RowBox[List["x", "+", RowBox[List["\[ImaginaryI]", " ", "y"]]]]]], "]"]], "]"]], "\[Equal]", " ", RowBox[List[UnderoverscriptBox["\[Sum]", RowBox[List["j", "=", "0"]], RowBox[List["Floor", "[", RowBox[List[RowBox[List["(", RowBox[List["n", "-", "1"]], ")"]], "/", "2"]], "]"]]], RowBox[List[FractionBox[RowBox[List[SuperscriptBox[RowBox[List["(", RowBox[List["-", "1"]], ")"]], "j"], " ", RowBox[List["Pochhammer", "[", RowBox[List[RowBox[List["n", "+", "a", "+", "b", "+", "1"]], ",", RowBox[List[RowBox[List["2", "j"]], "+", "1"]]]], "]"]]]], RowBox[List[SuperscriptBox["2", RowBox[List[RowBox[List["2", " ", "j"]], "+", "1"]]], RowBox[List[RowBox[List["(", RowBox[List[RowBox[List["2", "j"]], "+", "1"]], ")"]], "!"]]]]], RowBox[List["JacobiP", "[", RowBox[List[RowBox[List["n", "-", RowBox[List["2", "j"]], "-", "1"]], ",", RowBox[List["a", "+", RowBox[List["2", "j"]], "+", "1"]], ",", RowBox[List["b", "+", RowBox[List["2", "j"]], "+", "1"]], ",", "x"]], "]"]], " ", SuperscriptBox["y", RowBox[List[RowBox[List["2", "j"]], "+", "1"]]]]]]]]], "/;", RowBox[List[RowBox[List["x", "\[Element]", "Reals"]], "\[And]", RowBox[List["y", "\[Element]", "Reals"]], "\[And]", RowBox[List["a", "\[Element]", "Reals"]], "\[And]", RowBox[List["b", "\[Element]", "Reals"]], "\[And]", RowBox[List["n", "\[Element]", "Integers"]], "\[And]", RowBox[List["n", "\[GreaterEqual]", "0"]]]]]]]] | 
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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>  <mi> Im </mi>  <mo> ⁡ </mo>  <mo> ( </mo>  <mrow>  <msubsup>  <mi> P </mi>  <mi> n </mi>  <mrow>  <mo> ( </mo>  <mrow>  <mi> a </mi>  <mo> , </mo>  <mi> b </mi>  </mrow>  <mo> ) </mo>  </mrow>  </msubsup>  <mo> ( </mo>  <mrow>  <mi> x </mi>  <mo> + </mo>  <mrow>  <mi> ⅈ </mi>  <mo> ⁢ </mo>  <mi> y </mi>  </mrow>  </mrow>  <mo> ) </mo>  </mrow>  <mo> ) </mo>  </mrow>  <mo> ⩵ </mo>  <mrow>  <munderover>  <mo> ∑ </mo>  <mrow>  <mi> j </mi>  <mo> = </mo>  <mn> 0 </mn>  </mrow>  <mrow>  <mo> ⌊ </mo>  <mfrac>  <mrow>  <mi> n </mi>  <mo> - </mo>  <mn> 1 </mn>  </mrow>  <mn> 2 </mn>  </mfrac>  <mo> ⌋ </mo>  </mrow>  </munderover>  <mrow>  <mfrac>  <mrow>  <msup>  <mrow>  <mo> ( </mo>  <mrow>  <mo> - </mo>  <mn> 1 </mn>  </mrow>  <mo> ) </mo>  </mrow>  <mi> j </mi>  </msup>  <mo> ⁢ </mo>  <semantics>  <msub>  <mrow>  <mo> ( </mo>  <mrow>  <mi> a </mi>  <mo> + </mo>  <mi> b </mi>  <mo> + </mo>  <mi> n </mi>  <mo> + </mo>  <mn> 1 </mn>  </mrow>  <mo> ) </mo>  </mrow>  <mrow>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mi> j </mi>  </mrow>  <mo> + </mo>  <mn> 1 </mn>  </mrow>  </msub>  <annotation encoding='Mathematica'> TagBox[SubscriptBox[RowBox[List["(", RowBox[List["a", "+", "b", "+", "n", "+", "1"]], ")"]], RowBox[List[RowBox[List["2", " ", "j"]], "+", "1"]]], Pochhammer] </annotation>  </semantics>  <mo> ⁢ </mo>  <msup>  <mi> y </mi>  <mrow>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mi> j </mi>  </mrow>  <mo> + </mo>  <mn> 1 </mn>  </mrow>  </msup>  </mrow>  <mrow>  <msup>  <mn> 2 </mn>  <mrow>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mi> j </mi>  </mrow>  <mo> + </mo>  <mn> 1 </mn>  </mrow>  </msup>  <mo> ⁢ </mo>  <mrow>  <mrow>  <mo> ( </mo>  <mrow>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mi> j </mi>  </mrow>  <mo> + </mo>  <mn> 1 </mn>  </mrow>  <mo> ) </mo>  </mrow>  <mo> ! </mo>  </mrow>  </mrow>  </mfrac>  <mo> ⁢ </mo>  <mrow>  <msubsup>  <mi> P </mi>  <mrow>  <mrow>  <mrow>  <mo> - </mo>  <mn> 2 </mn>  </mrow>  <mo> ⁢ </mo>  <mi> j </mi>  </mrow>  <mo> + </mo>  <mi> n </mi>  <mo> - </mo>  <mn> 1 </mn>  </mrow>  <mrow>  <mo> ( </mo>  <mrow>  <mrow>  <mi> a </mi>  <mo> + </mo>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mi> j </mi>  </mrow>  <mo> + </mo>  <mn> 1 </mn>  </mrow>  <mo> , </mo>  <mrow>  <mi> b </mi>  <mo> + </mo>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mi> j </mi>  </mrow>  <mo> + </mo>  <mn> 1 </mn>  </mrow>  </mrow>  <mo> ) </mo>  </mrow>  </msubsup>  <mo> ( </mo>  <mi> x </mi>  <mo> ) </mo>  </mrow>  </mrow>  </mrow>  </mrow>  <mtext>   </mtext>  <mo> /; </mo>  <mrow>  <mrow>  <mi> x </mi>  <mo> ∈ </mo>  <semantics>  <mi> ℝ </mi>  <annotation encoding='Mathematica'> TagBox["\[DoubleStruckCapitalR]", Function[Reals]] </annotation>  </semantics>  </mrow>  <mo> ∧ </mo>  <mrow>  <mi> y </mi>  <mo> ∈ </mo>  <semantics>  <mi> ℝ </mi>  <annotation encoding='Mathematica'> TagBox["\[DoubleStruckCapitalR]", Function[Reals]] </annotation>  </semantics>  </mrow>  <mo> ∧ </mo>  <mrow>  <mi> a </mi>  <mo> ∈ </mo>  <semantics>  <mi> ℝ </mi>  <annotation encoding='Mathematica'> TagBox["\[DoubleStruckCapitalR]", Function[Reals]] </annotation>  </semantics>  </mrow>  <mo> ∧ </mo>  <mrow>  <mi> b </mi>  <mo> ∈ </mo>  <semantics>  <mi> ℝ </mi>  <annotation encoding='Mathematica'> TagBox["\[DoubleStruckCapitalR]", Function[Reals]] </annotation>  </semantics>  </mrow>  <mo> ∧ </mo>  <mrow>  <mi> n </mi>  <mo> ∈ </mo>  <mi> ℕ </mi>  </mrow>  </mrow>  </mrow>  <annotation-xml encoding='MathML-Content'>  <apply>  <ci> Condition </ci>  <apply>  <eq />  <apply>  <imaginary />  <apply>  <ci> JacobiP </ci>  <ci> n </ci>  <ci> a </ci>  <ci> b </ci>  <apply>  <plus />  <ci> x </ci>  <apply>  <times />  <imaginaryi />  <ci> y </ci>  </apply>  </apply>  </apply>  </apply>  <apply>  <sum />  <bvar>  <ci> j </ci>  </bvar>  <lowlimit>  <cn type='integer'> 0 </cn>  </lowlimit>  <uplimit>  <apply>  <floor />  <apply>  <times />  <apply>  <plus />  <ci> n </ci>  <cn type='integer'> -1 </cn>  </apply>  <apply>  <power />  <cn type='integer'> 2 </cn>  <cn type='integer'> -1 </cn>  </apply>  </apply>  </apply>  </uplimit>  <apply>  <times />  <apply>  <times />  <apply>  <power />  <cn type='integer'> -1 </cn>  <ci> j </ci>  </apply>  <apply>  <ci> Pochhammer </ci>  <apply>  <plus />  <ci> a </ci>  <ci> b </ci>  <ci> n </ci>  <cn type='integer'> 1 </cn>  </apply>  <apply>  <plus />  <apply>  <times />  <cn type='integer'> 2 </cn>  <ci> j </ci>  </apply>  <cn type='integer'> 1 </cn>  </apply>  </apply>  <apply>  <power />  <ci> y </ci>  <apply>  <plus />  <apply>  <times />  <cn type='integer'> 2 </cn>  <ci> j </ci>  </apply>  <cn type='integer'> 1 </cn>  </apply>  </apply>  <apply>  <power />  <apply>  <times />  <apply>  <power />  <cn type='integer'> 2 </cn>  <apply>  <plus />  <apply>  <times />  <cn type='integer'> 2 </cn>  <ci> j </ci>  </apply>  <cn type='integer'> 1 </cn>  </apply>  </apply>  <apply>  <factorial />  <apply>  <plus />  <apply>  <times />  <cn type='integer'> 2 </cn>  <ci> j </ci>  </apply>  <cn type='integer'> 1 </cn>  </apply>  </apply>  </apply>  <cn type='integer'> -1 </cn>  </apply>  </apply>  <apply>  <ci> JacobiP </ci>  <apply>  <plus />  <apply>  <times />  <cn type='integer'> -2 </cn>  <ci> j </ci>  </apply>  <ci> n </ci>  <cn type='integer'> -1 </cn>  </apply>  <apply>  <plus />  <ci> a </ci>  <apply>  <times />  <cn type='integer'> 2 </cn>  <ci> j </ci>  </apply>  <cn type='integer'> 1 </cn>  </apply>  <apply>  <plus />  <ci> b </ci>  <apply>  <times />  <cn type='integer'> 2 </cn>  <ci> j </ci>  </apply>  <cn type='integer'> 1 </cn>  </apply>  <ci> x </ci>  </apply>  </apply>  </apply>  </apply>  <apply>  <and />  <apply>  <in />  <ci> x </ci>  <reals />  </apply>  <apply>  <in />  <ci> y </ci>  <reals />  </apply>  <apply>  <in />  <ci> a </ci>  <reals />  </apply>  <apply>  <in />  <ci> b </ci>  <reals />  </apply>  <apply>  <in />  <ci> n </ci>  <ci> ℕ </ci>  </apply>  </apply>  </apply>  </annotation-xml>  </semantics>  </math> 
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 | | Cell[BoxData[RowBox[List[RowBox[List["HoldPattern", "[", RowBox[List["Im", "[", RowBox[List["JacobiP", "[", RowBox[List["n_", ",", "a_", ",", "b_", ",", RowBox[List["x_", "+", RowBox[List["\[ImaginaryI]", " ", "y_"]]]]]], "]"]], "]"]], "]"]], "\[RuleDelayed]", RowBox[List[RowBox[List[UnderoverscriptBox["\[Sum]", RowBox[List["j", "=", "0"]], RowBox[List["Floor", "[", FractionBox[RowBox[List["n", "-", "1"]], "2"], "]"]]], FractionBox[RowBox[List[RowBox[List["(", RowBox[List[SuperscriptBox[RowBox[List["(", RowBox[List["-", "1"]], ")"]], "j"], " ", RowBox[List["Pochhammer", "[", RowBox[List[RowBox[List["n", "+", "a", "+", "b", "+", "1"]], ",", RowBox[List[RowBox[List["2", " ", "j"]], "+", "1"]]]], "]"]]]], ")"]], " ", RowBox[List["JacobiP", "[", RowBox[List[RowBox[List["n", "-", RowBox[List["2", " ", "j"]], "-", "1"]], ",", RowBox[List["a", "+", RowBox[List["2", " ", "j"]], "+", "1"]], ",", RowBox[List["b", "+", RowBox[List["2", " ", "j"]], "+", "1"]], ",", "x"]], "]"]], " ", SuperscriptBox["y", RowBox[List[RowBox[List["2", " ", "j"]], "+", "1"]]]]], RowBox[List[SuperscriptBox["2", RowBox[List[RowBox[List["2", " ", "j"]], "+", "1"]]], " ", RowBox[List[RowBox[List["(", RowBox[List[RowBox[List["2", " ", "j"]], "+", "1"]], ")"]], "!"]]]]]]], "/;", RowBox[List[RowBox[List["x", "\[Element]", "Reals"]], "&&", RowBox[List["y", "\[Element]", "Reals"]], "&&", RowBox[List["a", "\[Element]", "Reals"]], "&&", RowBox[List["b", "\[Element]", "Reals"]], "&&", RowBox[List["n", "\[Element]", "Integers"]], "&&", RowBox[List["n", "\[GreaterEqual]", "0"]]]]]]]]]] | 
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 | | Date Added to functions.wolfram.com (modification date) | 
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