- #1
andrew.c
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Homework Statement
Find the general and, if possible, particular solutions of the following ordinary differential equations:
y''+9y=36sin3x
(hint: modification rule for PI)
Homework Equations
Knowledge of ODE's
[tex]y = y_{aux}+y_{particular}[/tex]
The Attempt at a Solution
I get the compementary function;
y''+9y = 0
and then using lambda-notation
[tex]\lambda^2 + 9 = 0[/tex]
therefore
[tex]\lambda = \pm 3i[/tex]
(complex roots)
so
[tex]y_{aux} = A cos 3x + B sin 3x[/tex]
but now how do I get [tex]y_{particular}[/tex]??