Solve Power Series: (x^2)(y") + y = 0

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SUMMARY

The differential equation (x^2)(y") + y = 0 is singular at x=0, making it impossible to expand in a power series around this point. To solve it using power series, one must shift the expansion point. By substituting u = x + 1, the equation transforms into (u-1)^2*y'' + y = 0, allowing for a valid power series expansion around u. This method effectively circumvents the singularity issue at x=0.

PREREQUISITES
  • Understanding of differential equations, specifically second-order linear equations.
  • Familiarity with power series and their convergence properties.
  • Knowledge of substitution methods in solving differential equations.
  • Basic calculus, including differentiation and series expansion techniques.
NEXT STEPS
  • Study the method of power series solutions for differential equations.
  • Learn about singular points in differential equations and their implications.
  • Explore substitution techniques in solving differential equations.
  • Investigate the convergence of power series and their applications in differential equations.
USEFUL FOR

Students and educators in mathematics, particularly those focusing on differential equations and power series methods. This discussion is beneficial for anyone looking to deepen their understanding of solving singular differential equations.

momen salah
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Homework Statement



solve using power series:
(x^2)(y")+y=0


Homework Equations





The Attempt at a Solution



after solving it i stopped at :

an[n^2-n+1]=0
 
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Your problems are coming from the fact that the differential equation is singular at 0. You can't expand it in a power series around x=0. You'll have to expand around another point if you want to do it that way. For example let u=x+1. Then the equation becomes (u-1)^2*y''+y=0. Now expand it as a series in u.
 

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