*Here, you find my whole video series about Ordinary Differential Equations in the correct order and I also help you with some text around the videos. If you want to test your knowledge, please use the quizzes, and consult the PDF version of the video if needed. When you have any questions, you can use the comments below and ask anything. However, without further ado let’s start:*

#### Part 1 - Introduction

**Ordinary Differential Equations** is a video series I started for everyone who is interested in the theory of differential equations and dynamics and also in concrete solution methods.:

With this you now know the topics that we will discuss in this series. Now, in the next video let us discuss **definitions** in the topic.

#### Part 2 - Definitions

There are a lot of notions one has to define to get a precise definition what a differential equation is and what it means to find solutions for it. Let’s do it:

#### Part 3 - Directional Field

After defining all these new manners of speaking, we are ready to go to a more visual approach. The **direction field** is essentially just a graph visualisation of a vector-valued function but it helps a lot to get properties from a given differential equation. We will first look at one- and two-dimensional examples.

#### Part 4 - Reducing to First Order

We already used it in the last video: the fact that every ordinary differential equations could be described as a system of first order. Now we will fill in these gaps and show the correct substitutions, one needs to get this result.