---
tag: 0Q1FKQKTKJ
kind: concept
name: Exact equation
aliases: [exact-differential-equation]
msc: [34A05]
sources:
  - url: https://en.wikipedia.org/wiki/Exact_differential_equation
    locator: lead section
same_as:
  wikidata: Q1366795
  wikipedia: Exact differential equation
---

## Summary

An exact equation is a first-order equation $M\, dx + N\, dy = 0$ whose left side is the total differential of a function $\psi(x, y)$.
Its solutions lie on the level curves $\psi(x, y) = C$. See the [[definition|0EC7AGJ0PX]].