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MAT244--2018F
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non-homogeneous guessing question
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Topic: non-homogeneous guessing question (Read 688 times)
Weina Zhu
Jr. Member
Posts: 6
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non-homogeneous guessing question
«
on:
October 08, 2018, 10:37:22 AM »
during solving the general solution for the non-homogeneous equation, why should we guessing an answer combine sin&cos together for
an equation like the right-hand side only contains one of the sin&cos.
Thanks!
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Victor Ivrii
Administrator
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Re: non-homogeneous guessing question
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Reply #1 on:
October 08, 2018, 01:11:46 PM »
Because derivative of sine is cosine and v.v. Try to solve $y''+y'=\cos(x)$ as with $y=a\cos(x)$.
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Last Edit: October 08, 2018, 01:35:11 PM by Victor Ivrii
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MAT244--2018F
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non-homogeneous guessing question