I have a problem which in involves a second order differential equations with imaginary roots and I can seem to know how to finish the problem.(adsbygoogle = window.adsbygoogle || []).push({});

d^2y/dt^2 +15y =cos 4t+2 sin t

this is what I got so far

r^2+15=0 for the homogeneous part

r=+-(√15)

Yh=C1cos√15+C2sin√15

now is where I get stuck

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# 2nd order nonhomogeneos differential equations with initial conditions

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