---
tag: 0R9PHTGVNW
kind: concept
name: One-sided derivative
msc: [26A24]
sources:
  - url: https://en.wikipedia.org/wiki/Semi-differentiability
    locator: lead section
same_as:
  wikidata: Q4370927
  wikipedia: Semi-differentiability
---

## Summary

A one-sided derivative is the limit of difference quotients from one side of a point only. A function is differentiable at an interior point exactly when its left and right derivatives exist and agree. The node [[one-sided derivative|0HXEX0DPRA]] gives the precise definition.