Solve De 1 F78748
1. The problem is to solve the differential equation $y'' + 3y' + 2y = 6$ using the method of undetermined coefficients.
2. The general approach is to find the complementary solution $y_c$ by solving the homogeneous equation $y'' + 3y' + 2y = 0$ and then find a particular solution $y_p$ for the nonhomogeneous part.
3. Solve the characteristic equation for the homogeneous part:
$$r^2 + 3r + 2 = 0$$
Factor:
$$(r + 1)(r + 2) = 0$$
So,
$$r = -1, -2$$
4. The complementary solution is:
$$y_c = C_1 e^{-x} + C_2 e^{-2x}$$
5. For the particular solution, since the right side is a constant $6$, try a constant solution:
$$y_p = A$$
6. Substitute $y_p$ into the differential equation:
$$0 + 0 + 2A = 6$$
So,
$$2A = 6 \implies A = 3$$
7. The general solution is:
$$y = y_c + y_p = C_1 e^{-x} + C_2 e^{-2x} + 3$$
This completes the solution for problem 1.