Is the Integral of 1/sinh^2(x/2) a Principal Value Integral?

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Discussion Overview

The discussion revolves around the evaluation of the integral of \( \frac{1}{\sinh^2(x/2)} \) from negative infinity to positive infinity. Participants are questioning whether this integral should be considered a principal value integral and are clarifying the nature of the expression on the right-hand side of the equation.

Discussion Character

  • Debate/contested, Mathematical reasoning

Main Points Raised

  • One participant presents the integral \( \int_{-\infty}^{\infty} \frac{1}{\sinh^2(x/2)} \, dx \) and questions if it should be treated as a principal value integral.
  • Another participant points out that the right-hand side of the equation cannot contain \( x \) if integrating with respect to \( x \).
  • A participant reiterates the integral and seeks clarification on whether the goal is to evaluate the integral or prove the anti-derivative.
  • There is a discussion about the implications of defining the integral with limits, suggesting it changes the nature of the expression.

Areas of Agreement / Disagreement

Participants express differing views on the nature of the integral and whether it should be treated as a principal value integral, indicating that the discussion remains unresolved.

Contextual Notes

There are ambiguities regarding the interpretation of the integral and the definitions involved, particularly concerning the treatment of limits and the relationship to anti-derivatives.

Belgium 12
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Hi dear members,
I have a problem with the following integral:

Integral 1/sinh^2(x/2) from -inf to +inf =-2 coth(x/2)

must I consider it as a principal value integral?

Thank you
 
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If you're integrating wrt x, you can't have x in the RHS.
 
Belgium 12 said:
Integral 1/sinh^2(x/2) from -inf to +inf =-2 coth(x/2)

Just to be clear, are you trying to evaluate
##\int_{-\infty}^{\infty} \frac{1}{\sinh ^2(x/2)} \, dx##
 
once you put limits on the integral (a definite integral, not an indefinite integral), it is no longer a function of x. is it the anti-derivative you want to prove?
 

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