I have a Wronskian Question?If the Wronskian W of f and g is t^2*e^t

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Discussion Overview

The discussion revolves around solving for a function g(t) given the Wronskian W of two functions f and g, specifically W = t^2*e^t, with f(t) defined as t. The scope includes mathematical reasoning and problem-solving techniques related to differential equations and the properties of Wronskians.

Discussion Character

  • Mathematical reasoning, Homework-related, Technical explanation

Main Points Raised

  • One participant sets up the problem using the definition of the Wronskian and attempts to derive g(t) from W = t^2*e^t.
  • Another participant suggests using the quotient rule to simplify the expression involving the Wronskian.
  • A third participant expresses difficulty in reaching the correct answer, indicating their work leads to an expression involving (te^t)(t-1) + c.
  • A fourth participant questions the validity of the term t-1 in the expression, suggesting it does not belong.

Areas of Agreement / Disagreement

Participants express differing views on the correctness of the derived expressions, indicating that there is no consensus on the solution to the problem. Disagreement exists regarding the validity of specific terms in the equations presented.

Contextual Notes

Participants do not clarify certain assumptions or steps in their mathematical reasoning, and the discussion includes unresolved aspects of the problem-solving process.

roymkim
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I have a Wronskian Question?
If the Wronskian W of f and g is t^2*e^t and if f(t)=t, find g(t).

I have tried setting up this problem:

tg'-t'g = t^2*e^t
tg'-g = t^2*e^t

Setting up the integrating factor, µ= e^∫-1 --> µ= e^-t
(e^-t)t*g' - (e^-t)*g = (e^-t)(t^2*e^t)

so preferably I would want to be able to set up the equation as (fg)' = (e^-t)(t^2*e^t)

but the derivative of (e^-t)t is not (e^-t).

The answer is supposed to be te^t+ct
 
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The quotient rule is handy here
f g'-f' g=f2(g/f)'

f g'-f' g=t2(g/t)'=t2et
 


I'm still not getting the right answer.

I get it down to (te^t)(t-1)+ct
 


Where are you getting that t-1? It clearly does not belong.
 

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