---
tag: 0J0FCWV32D
kind: concept
name: Exponential function
msc: [33B10, 26A09]
sources:
  - url: https://en.wikipedia.org/wiki/Exponential_function
    locator: lead section
same_as:
  wikidata: Q168698
  wikipedia: Exponential function
---

## Summary

The exponential function $x \mapsto e^x$ is the function that equals its own derivative and takes the value $1$ at $0$. It turns sums into products, and it is the sum of the power series $\sum x^n / n!$. The node [[exponential function|0RMVS7RXZX]] gives the precise definition.