Difference between revisions of "Logarithmic derivative of Jacobi theta 1 equals cotangent + a sum of sines"

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==References==
 
==References==
* {{BookReference|Handbook of mathematical functions|1964|Milton Abramowitz|author2=Irene A. Stegun|prev=Derivative of Jacobi theta 1 at 0|next=Logarithmic derivative of Jacobi theta 2 equals negative tangent + a sum of sines}}: 16.29.1
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* {{BookReference|Handbook of mathematical functions|1964|Milton Abramowitz|author2=Irene A. Stegun|prev=Derivative of Jacobi theta 1 at 0|next=Logarithmic derivative of Jacobi theta 2 equals negative tangent + a sum of sines}}: $16.29.1$
  
 
[[Category:Theorem]]
 
[[Category:Theorem]]
 
[[Category:Unproven]]
 
[[Category:Unproven]]

Latest revision as of 18:04, 5 July 2016

Theorem

The following formula holds: $$\dfrac{\vartheta_1'(u,q)}{\vartheta_1(u,q)} = \cot(u)+4\displaystyle\sum_{k=1}^{\infty} \dfrac{q^{2k}}{1-q^{2k}} \sin(2ku),$$ where $\vartheta_1$ denots the Jacobi theta 1, $\cot$ denotes cotangent, and $\sin$ denotes sine.

Proof

References