We can now use power series to also solve differential equations.
\begin{equation} \dv{x}{t} = 0; x(0)=1 \end{equation}
We wish to have a power-series solution of shape:
\begin{equation} x(t) = \sum_{k=0}^{\infty }a_{k}t^{k} \end{equation}
We want to find the coefficients a_{k}. If you can find such a function that fits this form, they both 1) converge and 20 behave the same way as e^{x} does in Simple Differential Equations. analytic functions Functions which can be described with a power series are called analytic functions.