# Differential equations/Change of variables

Educational level: this is a tertiary (university) resource. |

Type classification: this is a lesson resource. |

Subject classification: this is a mathematics resource. |

Completion status: this resource is ~25% complete. |

### DefinitionEdit

In a differential equation, if a certain term appears many different times, a substitution can be made similar to a -substitution.

### SolutionEdit

- Substitute a term for a variable (e.g. ).
- Implicitly differentiate the variable (e.g. ).
- Solve for the derivative that needs to be solved (e.g. ).
- Solve the original equation in terms of and then use the substitution for to get the original equation back in terms of and .