Suppose that $y$ is the sum of a Dirichlet series:
$$\forall x \in \mathbf { R } _ { + } \quad y ( x ) = \sum _ { n = 0 } ^ { + \infty } a _ { n } \mathrm { e } ^ { - \lambda _ { n } x },$$
where $y(0) = 0$ and $\lim_{x\to+\infty} y(x) = c$. Express $a _ { 0 }$ and $b _ { 0 }$ in terms of the constant $c$ introduced in Part I.