  
| 
 | 
  
  | 
  
  | 
  
  | 
 
  
  | 
 
  
  | 
  
  | 
 
 
  
  | 
  
  | 
  
  | 
 
  
  | 
 
  
  | 
  
  | 
 
 
  
  | 
  
  | 
  
  | 
 
  
  | 
 
  
  | 
  
  | 
 
 
  
  | 
  
  | 
  
  | 
 
  
  
 |  
  
  | 
  
  | 
  
  | 
 
  
  | 
 
  | 
  
  | 
 
  
  | 
  
  | 
  
  | 
 
  
  | 
 
  | 
   http://functions.wolfram.com/07.14.25.0005.01
   |   
  | 
  
  | 
 
  
  | 
  
  | 
  
  | 
 
  
  
 |  
 | 
  
  | 
 
  
  
 |  
  
  | 
  
  | 
  
  | 
 
  
  | 
    
  | 
  
  | 
 
  
  | 
  
  | 
  
  | 
 
  
  | 
 
  | 
    Sum[(Sqrt[(n! (\[Lambda] + n) Gamma[\[Lambda]]^2)/(Pi 2^(1 - 2 \[Lambda]) 
        Gamma[2 \[Lambda] + n])] (1 - x^2)^((2 \[Lambda] - 1)/4) 
     GegenbauerC[n, \[Lambda], x]) 
    (Sqrt[(n! (\[Lambda] + n) Gamma[\[Lambda]]^2)/(Pi 2^(1 - 2 \[Lambda]) 
        Gamma[2 \[Lambda] + n])] (1 - y^2)^((2 \[Lambda] - 1)/4) 
     GegenbauerC[n, \[Lambda], y]), {n, 0, Infinity}] == DiracDelta[x - y] /; 
 Re[\[Lambda]] > -(1/2) && \[Lambda] != 0 && -1 < x < 1 && -1 < y < 1 
   |   
  | 
  
  | 
 
  
  | 
  
  | 
  
  | 
 
  
  
 |  
  
  | 
  
  | 
  
  | 
 
  
  | 
    
  | 
  
  | 
 
  
  | 
  
  | 
  
  | 
 
  
  | 
 
  | 
   Cell[BoxData[RowBox[List[RowBox[List[RowBox[List[UnderoverscriptBox["\[Sum]", RowBox[List["n", "=", "0"]], "\[Infinity]"], RowBox[List[RowBox[List["(", RowBox[List[SqrtBox[FractionBox[RowBox[List[RowBox[List["n", "!"]], " ", RowBox[List["(", RowBox[List["\[Lambda]", "+", "n"]], ")"]], " ", SuperscriptBox[RowBox[List["Gamma", "[", "\[Lambda]", "]"]], "2"]]], RowBox[List["\[Pi]", " ", SuperscriptBox["2", RowBox[List["1", "-", RowBox[List["2", " ", "\[Lambda]"]]]]], " ", RowBox[List["Gamma", "[", RowBox[List[RowBox[List["2", " ", "\[Lambda]"]], "+", "n"]], "]"]]]]]], SuperscriptBox[RowBox[List["(", RowBox[List["1", "-", SuperscriptBox["x", "2"]]], ")"]], FractionBox[RowBox[List[RowBox[List["2", "\[Lambda]"]], "-", "1"]], "4"]], RowBox[List["GegenbauerC", "[", RowBox[List["n", ",", "\[Lambda]", ",", "x"]], "]"]]]], ")"]], RowBox[List["(", RowBox[List[SqrtBox[FractionBox[RowBox[List[RowBox[List["n", "!"]], " ", RowBox[List["(", RowBox[List["\[Lambda]", "+", "n"]], ")"]], " ", SuperscriptBox[RowBox[List["Gamma", "[", "\[Lambda]", "]"]], "2"]]], RowBox[List["\[Pi]", " ", SuperscriptBox["2", RowBox[List["1", "-", RowBox[List["2", " ", "\[Lambda]"]]]]], " ", RowBox[List["Gamma", "[", RowBox[List[RowBox[List["2", " ", "\[Lambda]"]], "+", "n"]], "]"]]]]]], SuperscriptBox[RowBox[List["(", RowBox[List["1", "-", SuperscriptBox["y", "2"]]], ")"]], FractionBox[RowBox[List[RowBox[List["2", "\[Lambda]"]], "-", "1"]], "4"]], RowBox[List["GegenbauerC", "[", RowBox[List["n", ",", "\[Lambda]", ",", "y"]], "]"]]]], ")"]]]]]], "\[Equal]", RowBox[List["DiracDelta", "[", RowBox[List["x", "-", "y"]], "]"]]]], "/;", RowBox[List[RowBox[List[RowBox[List["Re", "[", "\[Lambda]", "]"]], ">", RowBox[List["-", FractionBox["1", "2"]]]]], "\[And]", RowBox[List["\[Lambda]", "\[NotEqual]", "0"]], "\[And]", RowBox[List[RowBox[List["-", "1"]], "<", "x", "<", "1"]], "\[And]", RowBox[List[RowBox[List["-", "1"]], "<", "y", "<", "1"]]]]]]]] 
   |   
  | 
  
  | 
 
  
  | 
  
  | 
  
  | 
 
  
  
 |  
  
  | 
  
  | 
  
  | 
 
  
  | 
    
  | 
  
  | 
 
  
  | 
  
  | 
  
  | 
 
  
  | 
 
  
  | 
  
  | 
 
  
  | 
 
  | 
   
   <math xmlns='http://www.w3.org/1998/Math/MathML' mathematica:form='TraditionalForm' xmlns:mathematica='http://www.wolfram.com/XML/'>  <semantics>  <mrow>  <mrow>  <mrow>  <munderover>  <mo> ∑ </mo>  <mrow>  <mi> n </mi>  <mo> = </mo>  <mn> 0 </mn>  </mrow>  <mi> ∞ </mi>  </munderover>  <mrow>  <mrow>  <mo> ( </mo>  <mrow>  <msqrt>  <mfrac>  <mrow>  <mrow>  <mi> n </mi>  <mo> ! </mo>  </mrow>  <mo> ⁢ </mo>  <mrow>  <mo> ( </mo>  <mrow>  <mi> n </mi>  <mo> + </mo>  <mi> λ </mi>  </mrow>  <mo> ) </mo>  </mrow>  <mo> ⁢ </mo>  <msup>  <mrow>  <mi> Γ </mi>  <mo> ⁡ </mo>  <mo> ( </mo>  <mi> λ </mi>  <mo> ) </mo>  </mrow>  <mn> 2 </mn>  </msup>  </mrow>  <mrow>  <mi> π </mi>  <mo> ⁢ </mo>  <msup>  <mn> 2 </mn>  <mrow>  <mn> 1 </mn>  <mo> - </mo>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mi> λ </mi>  </mrow>  </mrow>  </msup>  <mo> ⁢ </mo>  <mrow>  <mi> Γ </mi>  <mo> ⁡ </mo>  <mo> ( </mo>  <mrow>  <mi> n </mi>  <mo> + </mo>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mi> λ </mi>  </mrow>  </mrow>  <mo> ) </mo>  </mrow>  </mrow>  </mfrac>  </msqrt>  <mo> ⁢ </mo>  <msup>  <mrow>  <mo> ( </mo>  <mrow>  <mn> 1 </mn>  <mo> - </mo>  <msup>  <mi> x </mi>  <mn> 2 </mn>  </msup>  </mrow>  <mo> ) </mo>  </mrow>  <mfrac>  <mrow>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mi> λ </mi>  </mrow>  <mo> - </mo>  <mn> 1 </mn>  </mrow>  <mn> 4 </mn>  </mfrac>  </msup>  <mo> ⁢ </mo>  <mrow>  <msubsup>  <mi> C </mi>  <mi> n </mi>  <mi> λ </mi>  </msubsup>  <mo> ( </mo>  <mi> x </mi>  <mo> ) </mo>  </mrow>  </mrow>  <mo> ) </mo>  </mrow>  <mo> ⁢ </mo>  <mrow>  <mo> ( </mo>  <mrow>  <msqrt>  <mfrac>  <mrow>  <mrow>  <mi> n </mi>  <mo> ! </mo>  </mrow>  <mo> ⁢ </mo>  <mrow>  <mo> ( </mo>  <mrow>  <mi> n </mi>  <mo> + </mo>  <mi> λ </mi>  </mrow>  <mo> ) </mo>  </mrow>  <mo> ⁢ </mo>  <msup>  <mrow>  <mi> Γ </mi>  <mo> ⁡ </mo>  <mo> ( </mo>  <mi> λ </mi>  <mo> ) </mo>  </mrow>  <mn> 2 </mn>  </msup>  </mrow>  <mrow>  <mi> π </mi>  <mo> ⁢ </mo>  <msup>  <mn> 2 </mn>  <mrow>  <mn> 1 </mn>  <mo> - </mo>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mi> λ </mi>  </mrow>  </mrow>  </msup>  <mo> ⁢ </mo>  <mrow>  <mi> Γ </mi>  <mo> ⁡ </mo>  <mo> ( </mo>  <mrow>  <mi> n </mi>  <mo> + </mo>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mi> λ </mi>  </mrow>  </mrow>  <mo> ) </mo>  </mrow>  </mrow>  </mfrac>  </msqrt>  <mo> ⁢ </mo>  <msup>  <mrow>  <mo> ( </mo>  <mrow>  <mn> 1 </mn>  <mo> - </mo>  <msup>  <mi> y </mi>  <mn> 2 </mn>  </msup>  </mrow>  <mo> ) </mo>  </mrow>  <mfrac>  <mrow>  <mrow>  <mn> 2 </mn>  <mo> ⁢ </mo>  <mi> λ </mi>  </mrow>  <mo> - </mo>  <mn> 1 </mn>  </mrow>  <mn> 4 </mn>  </mfrac>  </msup>  <mo> ⁢ </mo>  <mrow>  <msubsup>  <mi> C </mi>  <mi> n </mi>  <mi> λ </mi>  </msubsup>  <mo> ( </mo>  <mi> y </mi>  <mo> ) </mo>  </mrow>  </mrow>  <mo> ) </mo>  </mrow>  </mrow>  </mrow>  <mo> ⩵ </mo>  <mrow>  <semantics>  <mi> δ </mi>  <annotation-xml encoding='MathML-Content'>  <ci> DiracDelta </ci>  </annotation-xml>  </semantics>  <mo> ( </mo>  <mrow>  <mi> x </mi>  <mo> - </mo>  <mi> y </mi>  </mrow>  <mo> ) </mo>  </mrow>  </mrow>  <mo> /; </mo>  <mrow>  <mrow>  <mrow>  <mi> Re </mi>  <mo> ⁡ </mo>  <mo> ( </mo>  <mi> λ </mi>  <mo> ) </mo>  </mrow>  <mo> > </mo>  <mrow>  <mo> - </mo>  <mfrac>  <mn> 1 </mn>  <mn> 2 </mn>  </mfrac>  </mrow>  </mrow>  <mo> ∧ </mo>  <mrow>  <mi> λ </mi>  <mo> ≠ </mo>  <mn> 0 </mn>  </mrow>  <mo> ∧ </mo>  <mrow>  <mrow>  <mo> - </mo>  <mn> 1 </mn>  </mrow>  <mo> < </mo>  <mi> x </mi>  <mo> < </mo>  <mn> 1 </mn>  </mrow>  <mo> ∧ </mo>  <mrow>  <mrow>  <mo> - </mo>  <mn> 1 </mn>  </mrow>  <mo> < </mo>  <mi> y </mi>  <mo> < </mo>  <mn> 1 </mn>  </mrow>  </mrow>  </mrow>  <annotation-xml encoding='MathML-Content'>  <apply>  <ci> Condition </ci>  <apply>  <eq />  <apply>  <sum />  <bvar>  <ci> n </ci>  </bvar>  <lowlimit>  <cn type='integer'> 0 </cn>  </lowlimit>  <uplimit>  <infinity />  </uplimit>  <apply>  <times />  <apply>  <times />  <apply>  <power />  <apply>  <times />  <apply>  <factorial />  <ci> n </ci>  </apply>  <apply>  <plus />  <ci> n </ci>  <ci> λ </ci>  </apply>  <apply>  <power />  <apply>  <ci> Gamma </ci>  <ci> λ </ci>  </apply>  <cn type='integer'> 2 </cn>  </apply>  <apply>  <power />  <apply>  <times />  <pi />  <apply>  <power />  <cn type='integer'> 2 </cn>  <apply>  <plus />  <cn type='integer'> 1 </cn>  <apply>  <times />  <cn type='integer'> -1 </cn>  <apply>  <times />  <cn type='integer'> 2 </cn>  <ci> λ </ci>  </apply>  </apply>  </apply>  </apply>  <apply>  <ci> Gamma </ci>  <apply>  <plus />  <ci> n </ci>  <apply>  <times />  <cn type='integer'> 2 </cn>  <ci> λ </ci>  </apply>  </apply>  </apply>  </apply>  <cn type='integer'> -1 </cn>  </apply>  </apply>  <cn type='rational'> 1 <sep /> 2 </cn>  </apply>  <apply>  <power />  <apply>  <plus />  <cn type='integer'> 1 </cn>  <apply>  <times />  <cn type='integer'> -1 </cn>  <apply>  <power />  <ci> x </ci>  <cn type='integer'> 2 </cn>  </apply>  </apply>  </apply>  <apply>  <times />  <apply>  <plus />  <apply>  <times />  <cn type='integer'> 2 </cn>  <ci> λ </ci>  </apply>  <cn type='integer'> -1 </cn>  </apply>  <apply>  <power />  <cn type='integer'> 4 </cn>  <cn type='integer'> -1 </cn>  </apply>  </apply>  </apply>  <apply>  <apply>  <power />  <apply>  <ci> Subscript </ci>  <ci> C </ci>  <ci> n </ci>  </apply>  <ci> λ </ci>  </apply>  <ci> x </ci>  </apply>  </apply>  <apply>  <times />  <apply>  <power />  <apply>  <times />  <apply>  <factorial />  <ci> n </ci>  </apply>  <apply>  <plus />  <ci> n </ci>  <ci> λ </ci>  </apply>  <apply>  <power />  <apply>  <ci> Gamma </ci>  <ci> λ </ci>  </apply>  <cn type='integer'> 2 </cn>  </apply>  <apply>  <power />  <apply>  <times />  <pi />  <apply>  <power />  <cn type='integer'> 2 </cn>  <apply>  <plus />  <cn type='integer'> 1 </cn>  <apply>  <times />  <cn type='integer'> -1 </cn>  <apply>  <times />  <cn type='integer'> 2 </cn>  <ci> λ </ci>  </apply>  </apply>  </apply>  </apply>  <apply>  <ci> Gamma </ci>  <apply>  <plus />  <ci> n </ci>  <apply>  <times />  <cn type='integer'> 2 </cn>  <ci> λ </ci>  </apply>  </apply>  </apply>  </apply>  <cn type='integer'> -1 </cn>  </apply>  </apply>  <cn type='rational'> 1 <sep /> 2 </cn>  </apply>  <apply>  <power />  <apply>  <plus />  <cn type='integer'> 1 </cn>  <apply>  <times />  <cn type='integer'> -1 </cn>  <apply>  <power />  <ci> y </ci>  <cn type='integer'> 2 </cn>  </apply>  </apply>  </apply>  <apply>  <times />  <apply>  <plus />  <apply>  <times />  <cn type='integer'> 2 </cn>  <ci> λ </ci>  </apply>  <cn type='integer'> -1 </cn>  </apply>  <apply>  <power />  <cn type='integer'> 4 </cn>  <cn type='integer'> -1 </cn>  </apply>  </apply>  </apply>  <apply>  <apply>  <power />  <apply>  <ci> Subscript </ci>  <ci> C </ci>  <ci> n </ci>  </apply>  <ci> λ </ci>  </apply>  <ci> y </ci>  </apply>  </apply>  </apply>  </apply>  <apply>  <ci> DiracDelta </ci>  <apply>  <plus />  <ci> x </ci>  <apply>  <times />  <cn type='integer'> -1 </cn>  <ci> y </ci>  </apply>  </apply>  </apply>  </apply>  <apply>  <and />  <apply>  <gt />  <apply>  <real />  <ci> λ </ci>  </apply>  <apply>  <times />  <cn type='integer'> -1 </cn>  <cn type='rational'> 1 <sep /> 2 </cn>  </apply>  </apply>  <apply>  <neq />  <ci> λ </ci>  <cn type='integer'> 0 </cn>  </apply>  <apply>  <lt />  <cn type='integer'> -1 </cn>  <ci> x </ci>  <cn type='integer'> 1 </cn>  </apply>  <apply>  <lt />  <cn type='integer'> -1 </cn>  <ci> y </ci>  <cn type='integer'> 1 </cn>  </apply>  </apply>  </apply>  </annotation-xml>  </semantics>  </math> 
   
   |   
  | 
  
  | 
 
  
  | 
  
  | 
  
  | 
 
 
  |   
  |  
  |  
  |   
  |  |  
  |   
  |  
  |  
  |   
  | Cell[BoxData[RowBox[List[RowBox[List["HoldPattern", "[", RowBox[List[UnderoverscriptBox["\[Sum]", RowBox[List["n_", "=", "0"]], "\[Infinity]"], RowBox[List[RowBox[List["(", RowBox[List[SqrtBox[FractionBox[RowBox[List[RowBox[List["n_", "!"]], " ", RowBox[List["(", RowBox[List["\[Lambda]_", "+", "n_"]], ")"]], " ", SuperscriptBox[RowBox[List["Gamma", "[", "\[Lambda]_", "]"]], "2"]]], RowBox[List["\[Pi]", " ", SuperscriptBox["2", RowBox[List["1", "-", RowBox[List["2", " ", "\[Lambda]_"]]]]], " ", RowBox[List["Gamma", "[", RowBox[List[RowBox[List["2", " ", "\[Lambda]_"]], "+", "n_"]], "]"]]]]]], " ", SuperscriptBox[RowBox[List["(", RowBox[List["1", "-", SuperscriptBox["x_", "2"]]], ")"]], RowBox[List[FractionBox["1", "4"], " ", RowBox[List["(", RowBox[List[RowBox[List["2", " ", "\[Lambda]_"]], "-", "1"]], ")"]]]]], " ", RowBox[List["GegenbauerC", "[", RowBox[List["n_", ",", "\[Lambda]_", ",", "x_"]], "]"]]]], ")"]], " ", RowBox[List["(", RowBox[List[SqrtBox[FractionBox[RowBox[List[RowBox[List["n_", "!"]], " ", RowBox[List["(", RowBox[List["\[Lambda]_", "+", "n_"]], ")"]], " ", SuperscriptBox[RowBox[List["Gamma", "[", "\[Lambda]_", "]"]], "2"]]], RowBox[List["\[Pi]", " ", SuperscriptBox["2", RowBox[List["1", "-", RowBox[List["2", " ", "\[Lambda]_"]]]]], " ", RowBox[List["Gamma", "[", RowBox[List[RowBox[List["2", " ", "\[Lambda]_"]], "+", "n_"]], "]"]]]]]], " ", SuperscriptBox[RowBox[List["(", RowBox[List["1", "-", SuperscriptBox["y_", "2"]]], ")"]], RowBox[List[FractionBox["1", "4"], " ", RowBox[List["(", RowBox[List[RowBox[List["2", " ", "\[Lambda]_"]], "-", "1"]], ")"]]]]], " ", RowBox[List["GegenbauerC", "[", RowBox[List["n_", ",", "\[Lambda]_", ",", "y_"]], "]"]]]], ")"]]]]]], "]"]], "\[RuleDelayed]", RowBox[List[RowBox[List["DiracDelta", "[", RowBox[List["x", "-", "y"]], "]"]], "/;", RowBox[List[RowBox[List[RowBox[List["Re", "[", "\[Lambda]", "]"]], ">", RowBox[List["-", FractionBox["1", "2"]]]]], "&&", RowBox[List["\[Lambda]", "\[NotEqual]", "0"]], "&&", RowBox[List[RowBox[List["-", "1"]], "<", "x", "<", "1"]], "&&", RowBox[List[RowBox[List["-", "1"]], "<", "y", "<", "1"]]]]]]]]]]  |  
  |  
  |   
  |  
  |  
  | 
  
  
 |  
  
  | 
  
  | 
  
  | 
 
  
  | 
 
  | 
   Date Added to functions.wolfram.com (modification date)
   |   
  | 
  
  | 
 
  
  | 
  
  | 
  
  | 
 
  
  | 
 
  
  | 
  
  | 
 
  
  | 
  
  | 
  
  | 
 
 | 
  | 
  
  
  
 |  
 
 |