Difference between revisions of "Logarithmic derivative of Jacobi theta 2 equals negative tangent + a sum of sines"

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==References==
 
==References==
* {{BookReference|Handbook of mathematical functions|1964|Milton Abramowitz|author2=Irene A. Stegun|prev=Logarithmic derivative of Jacobi theta 1 equals cotangent + a sum of sines|next=Logarithmic derivative of Jacobi theta 3 equals a sum of sines}}: 16.29.2
+
* {{BookReference|Handbook of mathematical functions|1964|Milton Abramowitz|author2=Irene A. Stegun|prev=Logarithmic derivative of Jacobi theta 1 equals cotangent + a sum of sines|next=Logarithmic derivative of Jacobi theta 3 equals a sum of sines}}: $16.29.2$
  
 
[[Category:Theorem]]
 
[[Category:Theorem]]
 
[[Category:Unproven]]
 
[[Category:Unproven]]

Latest revision as of 18:04, 5 July 2016

Theorem

The following formula holds: $$\dfrac{\vartheta_2'(u,q)}{\vartheta_2(u,q)} = -\tan(u)+4\displaystyle\sum_{k=1}^{\infty} (-1)^k \dfrac{q^{2k}}{1-q^{2k}} \sin(2ku),$$ where $\vartheta_2$ denotes the Jacobi theta 2, $\tan$ denotes the tangent, and $\sin$ denotes sine.

Proof

References