Consider ${\rm x}\left(0\right)$ is a fix positive real number, and we have following equation:
$$ {\rm x}\left(t\right) =a - \left[1 - {\rm x}\left(0\right)\right]\exp\left(-\int_{0}^{t}{\rm x}\left(t_{1}\right)\,{\rm d}t_{1}\right) $$
Is there any way to solve the above equation ?. Do they always have solution ?.
Any help or reference is appreciated.
Note that
$$x'(t) = [1-x(0)] x(t) \, e^{-\int_0^t dt' \, x(t')} = x(t) [a-x(t)]$$