A Wronskian- variation of Params Problem

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SUMMARY

The discussion focuses on solving the differential equation y'' - 4y' + 4y = (12e^2x)/(x^4) using the variation of parameters method. The user correctly identifies the Wronskian as w = e^(4x) but struggles with the calculations for W1 and W2, which are derived from the integrals for u1 and u2. The community emphasizes the importance of correctly applying the variation of parameters method and clarifying the equations for the derivatives of the constants involved.

PREREQUISITES
  • Understanding of differential equations, specifically second-order linear equations.
  • Familiarity with the variation of parameters method for solving differential equations.
  • Knowledge of Wronskian determinants and their role in differential equations.
  • Ability to perform integration of exponential functions and rational functions.
NEXT STEPS
  • Review the derivation of Wronskian determinants in the context of differential equations.
  • Practice solving differential equations using the variation of parameters method.
  • Study the integration techniques for functions involving exponentials and polynomials.
  • Explore examples of applying the variation of parameters to similar differential equations.
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Students studying differential equations, educators teaching advanced mathematics, and anyone seeking to improve their problem-solving skills in applied mathematics.

Cocoleia
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Homework Statement


y''-4y'+4y=(12e^2x)/(x^4)
I am trying to solve this differential equation. I know you would use the variation of parameters method, and I am trouble with the wronskian. My solution manual doesn't actually use a wronskian so I can't verify my work

Homework Equations

The Attempt at a Solution


I end up with w=e^4x
w1=(-12e^4x)/(x^3)
w2=(12e^4x)/(x^4)
But at this point the integrals for u1 and u2 seem rather impossible.
 
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Cocoleia said:

Homework Statement


y''-4y'+4y=(12e^2x)/(x^4)
I am trying to solve this differential equation. I know you would use the variation of parameters method, and I am trouble with the wronskian. My solution manual doesn't actually use a wronskian so I can't verify my work

Homework Equations

The Attempt at a Solution


I end up with w=e^4x
w1=(-12e^4x)/(x^3)
w2=(12e^4x)/(x^4)
But at this point the integrals for u1 and u2 seem rather impossible.
Your Wronskian w=e4x is correct. but what are W1 and W2? What equations do you get for the derivative of the "constants"?
 
Last edited:
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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