Solve first order difference equation

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SUMMARY

The discussion focuses on solving the first order difference equation defined by x[n] - x[n-1] = n(n+1)/2 with the initial condition x[1] = 1. The homogeneous solution is derived from the characteristic equation r - 1 = 0, yielding a solution of the form yhn = C. For the particular solution, the user suggests a polynomial of degree three, An^3 + Bn^2 + Cn, as a suitable guess to accommodate the non-homogeneous term n(n+1)/2.

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  • Understanding of first order difference equations
  • Familiarity with homogeneous and particular solutions in difference equations
  • Knowledge of polynomial functions and their degrees
  • Ability to solve characteristic equations
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  • Learn about the method of undetermined coefficients for polynomial guesses
  • Explore the concept of characteristic equations in greater depth
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Students and educators in mathematics, particularly those studying difference equations, as well as anyone looking to enhance their problem-solving skills in discrete mathematics.

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Homework Statement


Solve the first order difference equation.

Homework Equations


x[n] - x[n-1] = n(n+1)/2
x[1] = 1



The Attempt at a Solution


Homogenous solution:
Characteristic equation:
r - 1 = 0 <=> r = 1
=> yhn = C * 1^n = C

Particular solution:
ypn = ?
I'm supposed to do some intelligent guess here. n(n+1)/2 is a polynomial of degree 2 and doesn't exist in yhn so i should be something like An(n+1) or An^2+Bn but Ican't get anything to work.
 
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I would guess a polynomial of order 1 degree higher than n(n+1)/2. Say An^3+Bn^2+Cn.
 

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