# 6.021/Notes/2006-09-07

## Differential Equations

First order: no terms of order higher than (such as )

Linear: no product of dependent variables such as

Homogenous: is a solution

### Solving first-order linear equations

General form:

Solving:

1. Find homogenous solution first
2. Assume solution is

General solution:

Only three things needed for all such 1st order linear equations: initial value , final value , time constant .

### Example problems

RC circuit, water tank, flux across cell