The indefinite integral of \( \frac{e^x}{1+x} \) is non-elementary and is closely related to the exponential integral function. It can be expressed as \( \int \frac{e^x}{1+x}dx = \frac{{\rm{Ei}}(x+1)}{e} + C \). This result highlights the complexity of integrating functions that involve both exponential and rational components. The exponential integral, denoted as Ei, plays a crucial role in this context. Understanding this integral is important for advanced calculus and mathematical analysis.