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- Thread starter krish
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- Jan 17, 2013

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What is \(\displaystyle w\) ? ,is it a constant or a function of $t$ ?

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I believe w is a constant.What is \(\displaystyle w\) ? ,is it a constant or a function of $t$ ?

- Jan 17, 2013

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Aha , try differentiating one of the equations and tell me if you got any ideas .I believe w is a constant.

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So I differentiated the second equation with respect to t:Aha , try differentiating one of the equations and tell me if you got any ideas .

v'' = -du/dt

Then I substitute first equation for du/dt:

v'' = -(v - w(t-5)) = -v + w(t-5)

v'' + v - w(t-5) = 0

Does it become: v'' + v = wt - 5w ? How does keeping the

And then I solve the IVP. Is this correct? But what if w is a function of t? Then I am confused, is that possible? Thank you for answering.

- Jan 17, 2013

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That seems a not-easy problem to deal with if we try the other differentiation we getSo I differentiated the second equation with respect to t:

v'' = -du/dt

Then I substitute first equation for du/dt:

v'' = -(v - w(t-5)) = -v + w(t-5)

v'' + v - w(t-5) = 0

Does it become: v'' + v = wt - 5w ? How does keeping thewmatter?

And then I solve the IVP. Is this correct? But what if w is a function of t? Then I am confused, is that possible? Thank you for answering.

\(\displaystyle u''+ut = 2- w \)

The problem will get more complicated if assumed that $w$ a function because we have a three functions and two equations !

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It might be solvable by Laplace but I don't know whether it is an acceptable solution ?

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Can w(t-5) be the Heavyside unit function?That seems a not-easy problem to deal with if we try the other differentiation we get

\(\displaystyle u''+ut = 2- w \)

The problem will get more complicated if assumed that $w$ a function because we have a three functions and two equations !

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It might be solvable by Laplace but I don't know whether it is an acceptable solution ?

- Jan 17, 2013

- 1,667

I don't know there is no indication , that depends on the source.Can w(t-5) be the Heavyside unit function?

From Where did you get that problem ?

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It's in the review questions in my Differential Equations textbook.I don't know there is no indication , that depends on the source.

From Where did you get that problem ?

- Jan 17, 2013

- 1,667

Ok , tell me the name of the textbook and the page number .It's in the review questions in my Differential Equations textbook.

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Differential Equations (From Engineering Viewpoint) - Dr. R.C. ShahOk , tell me the name of the textbook and the page number .

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