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MAT244--2020F
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Chapter 2
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Lec 0101 - 9/15 Question
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Topic: Lec 0101 - 9/15 Question (Read 970 times)
Brandon Adiwinata
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Lec 0101 - 9/15 Question
«
on:
September 20, 2020, 06:16:36 PM »
I had a question from the lecture about the Methods for solving a differential equation. As indicated in the photo, how do we get u'(sqrt(t^2+1)) = t after plugging in y = u(sqrt(t^2+1)) into the original inhomogeneous equation?
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Last Edit: September 20, 2020, 06:18:46 PM by Brandon Adiwinata
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RunboZhang
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Re: Lec 0101 - 9/15 Question
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Reply #1 on:
September 20, 2020, 07:12:43 PM »
Hi, I have plugged it in y and calculated the LHS. Computation is attached below.
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Victor Ivrii
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Re: Lec 0101 - 9/15 Question
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Reply #2 on:
September 20, 2020, 07:49:47 PM »
One should remember that plugging $y=uy_1$ into inhimogeneous equation leaves $u'y_1$ in the left-hand expression. If you do not remember this, therefore you just do not understand the method of variations and you should reread previous slides
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MAT244--2020F
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MAT244--Lectures & Home Assignments
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Chapter 2
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Lec 0101 - 9/15 Question