Power Series expansion of an eigenvalue

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SUMMARY

The discussion focuses on expanding the eigenvalue λ = [3 + √(1 + 4ε²)]V₀ / 2 as a power series in ε, specifically up to the second order. Participants emphasize the importance of utilizing known power series expansions, particularly for the term √(1 + 4ε²). The conversation highlights the necessity of adhering to forum guidelines, which discourage vague responses such as "Dunno." Ultimately, the goal is to derive a clear power series representation for the eigenvalue.

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  • Understanding of power series expansions
  • Familiarity with eigenvalues and eigenvectors
  • Knowledge of calculus, particularly Taylor series
  • Basic algebraic manipulation skills
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  • Learn how to derive Taylor series expansions for functions
  • Study the properties of eigenvalues in linear algebra
  • Explore the application of power series in physics and engineering
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Students and professionals in mathematics, physics, and engineering who are working with eigenvalues and power series expansions, particularly those seeking to enhance their understanding of perturbative methods.

ExplosivePete
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1. ... Expand the Eigenvalue as a power series in epsilon, up to second order:
λ=[3+√(1+4 ε^2)]V0 / 2

Homework Equations


I am familiar with power series, but I don't know how to expand this as one.[/B]

The Attempt at a Solution

:[/B] I have played around with the idea of using known power series of functions such as e^x, yet I haven't found a way to make that useful.
 
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Dunno is not good enough according to PF guidelines
But do I detect a term ##\sqrt{1+4\varepsilon^2}## in there ?
 
BvU said:
Dunno is not good enough according to PF guidelines
But do I detect a term ##\sqrt{1+4\varepsilon^2}## in there ?

Please review my post again. Hopefully it is both more legible and up to PF guidelines.
 
I still detect a term ##
\sqrt{1+4\varepsilon^2\;}## ! How would you develop that into a power series in ##\varepsilon##, up to second order ?

And the guidelines tell you 'Dunno' ('Don't know') isn't good enough...
 

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