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TsAmE
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Homework Statement
Find the constants A and B such that the function y = Asinx + Bcosx satisfies the differential equation y'' + y' - 2y = sinx
Homework Equations
None
The Attempt at a Solution
My attempt: y = Asin x + Bcosx
y' = Acosx - Bsinx
y'' = - Asin x - Bcosx
y'' + y' - 2y = sin x
- Asinx - Bcosx + Acosx - Bsinx - 2Asinx + 2Bcosx = sinx
- 3Asinx + Bcosx + Acosx - Bsinx = sinx...
I don't know if my working out is correct, but I couldn't figure out what to do from there.