Hi

given the nonhomogeneous linear differential-equation

with

and no explicit solution x(t) of the problem, i like to show that

in addition for i'm able to show that:

and

do you know any theory i'm allowed to use in this case? i just find some results in stabilitytheory for homogeneous case with a constant coefficient a(t).

thanks for any hints or suggestions in advance.

kind regards, debelix