Homework 3, due September 15, 2011.

Due at noon on Thursday, September 15, 2011.
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goodwine
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Homework 3, due September 15, 2011.

Post by goodwine »

Reading: Chapter 3.

Exercises: 2.9, 2.10 (9, 10 and 11 only), 2.14, 2.19, 2.21, 2.22 and 2.25 (2, 4, 6 and 8 only).
Bill Goodwine, 376 Fitzpatrick
Jessie

Re: Homework 3, due September 15, 2011.

Post by Jessie »

For linear first order differential non homogeneous equations with variable coefficients are there two different methods that you can use to find the general solution? (Problem 2.21) I know that you can use variation of parameters but undetermined coefficients does not work. Thanks
goodwine
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Re: Homework 3, due September 15, 2011.

Post by goodwine »

Jessie wrote:For linear first order differential non homogeneous equations with variable coefficients are there two different methods that you can use to find the general solution? (Problem 2.21) I know that you can use variation of parameters but undetermined coefficients does not work. Thanks
The methods for nonlinear first order (separable or exact) may work even though the equation is linear.
Bill Goodwine, 376 Fitzpatrick
sschwane

Re: Homework 3, due September 15, 2011.

Post by sschwane »

Jessie wrote:For linear first order differential non homogeneous equations with variable coefficients are there two different methods that you can use to find the general solution? (Problem 2.21) I know that you can use variation of parameters but undetermined coefficients does not work. Thanks
I thought the same thing at first, but undetermined coefficients will work if you get the original equation in the right form before you start it.
goodwine
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Re: Homework 3, due September 15, 2011.

Post by goodwine »

sschwane wrote:
Jessie wrote:For linear first order differential non homogeneous equations with variable coefficients are there two different methods that you can use to find the general solution? (Problem 2.21) I know that you can use variation of parameters but undetermined coefficients does not work. Thanks
I thought the same thing at first, but undetermined coefficients will work if you get the original equation in the right form before you start it.
I don't see how you can convert it to a constant coefficient equation so that undetermined coefficients works, so in general that will not be a viable approach for this type of equation. However, there is no point in being too formalistic, and if you found a way that gives the right solution, then it's ok.
Bill Goodwine, 376 Fitzpatrick
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