pkg load symbolic
syms y(t)

ecuatia1 = diff(y(t), 2) + 3*y(t) == 9
dsolve(ecuatia1)

ecuatia2 = diff(y(t), 2) - 5*diff(y(t), 1) == t*e^t
dsolve(ecuatia2)

ecuatia3 = diff(y(t), 2) - 2*diff(y(t), 1) + y(t) == 8*e^t
dsolve(ecuatia3)

ecuatia4 = 4*diff(y(t), 2) + 11*diff(y(t), 1) - 3*y(t) == -2*t*e^(-3*t)
dsolve(ecuatia4)

ecuatia5 = diff(y(t), 2) - y(t) == t*sin(t)
dsolve(ecuatia5)

ecuatia6 = diff(y(t), 2) + y(t) == t*sin(t)
dsolve(ecuatia6)

ecuatia7 = diff(y(t), 2) + 2*diff(y(t), 1) + 2*y(t) == 4*t*e^(-t)*cos(t)
dsolve(ecuatia7)

ecuatia8 = diff(y(t), 2) - 4*y(t) == 8*sin(2*t)
dsolve(ecuatia8)