Problem 4. Consider the second order linear nonhomogeneous equation
$$L[y] = y'' + p(t)y' + q(t)y = g(t).$$
For each of the following determine whether the statement is true or false. Be sure to justify
your answer!
(a) If $\phi_1$ and $\phi_2$ are solutions of the nonhomogeneous equation $L[y] = g(t)$, then $\phi_1 + \phi_2$
is also a solution of $L[y] = g(t)$.
(b) If $\phi_1$ and $\phi_2$ are solutions of the nonhomogeneous equation $L[y] = g(t)$, then $\phi_1 - \phi_2$
is a solution of the homogeneous equation $L[y] = 0$.
(c) If $\phi_1$ is a solution of the nonhomogeneous equation $L[y] = g(t)$, and $\phi_2$ is a solution of
the homogeneous equation $L[y] = 0$, then $\phi_1 + \phi_2$ is a solution of $L[y] = g(t)$.