Why Must B Approach Zero in Cauchy-Euler ODE Solutions at x=0?

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Discussion Overview

The discussion revolves around the behavior of solutions to Cauchy-Euler ordinary differential equations (ODEs) at the boundary condition of x=0, specifically addressing why the coefficient B in the solution form must approach zero under certain conditions.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions why the coefficient B must go to zero at x=0, suggesting there may be a deeper explanation for this requirement.
  • Another participant explains that the negative exponent of the B term leads to a divergent solution at x=0, which contradicts physical interpretations in contexts like electron wave functions.
  • A different participant acknowledges the divergence at infinity but expresses confusion about the implications at x=0, seeking further clarification.
  • One participant notes that substituting x=0 into the term Bx^{-k} results in a division by zero, reinforcing the argument for setting B to zero.
  • A later reply reflects a personal realization about the simplicity of the explanation, indicating that confusion often arises from the complexity of texts on the subject.

Areas of Agreement / Disagreement

Participants express varying levels of understanding regarding the implications of the coefficient B at x=0, with some agreeing on the necessity of setting B to zero due to divergence, while others seek further clarification on the reasoning behind this requirement. The discussion remains unresolved in terms of a comprehensive explanation for all participants.

Contextual Notes

Some assumptions about the physical context of the solutions and the definitions of divergence may not be fully articulated, leading to different interpretations among participants.

Andreol263
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Why these ODEs when applied some boundary conditions, like x = 0, their solution of the form Ax^k + Bx^(-k), B WILL have to go to zero?Like some problems which involve spherical harmonics...
 
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The negative exponent of the B coefficient term implies divergent solution at x=0. If you are considering solutions with physical interpretation such as electron wave functions then the physical application is contradicted by the divergence at infinity. Those solutions don't apply and you set B = 0.
 
Yeah i understand why when x->infinity the solution is inconsistent, cause it's blow up, but i simply don't get it WHY x=0 implies in a divergent solution and B has to be 0, there's a more deep explanation?
 
[itex]B x^{-k}=\frac{B}{x^k} = \frac{B}{0}[/itex] when [itex]x=0[/itex].
 
Oh damn, I'm stupid , i was thinking in that, but it appears so simple that i forget this option because some texts are very confusing , and thank you so much for killing that existential question for me :D...
 

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