# What is a differential equation | Summary and Q&A

2.1M views
August 28, 2008
by
What is a differential equation

## TL;DR

This video introduces differential equations, which involve unknown functions and their derivatives, and explains their applications in various fields.

## Key Insights

• ❓ Differential equations are equations that involve unknown functions and their derivatives.
• #️⃣ The solution to a differential equation is a function rather than a number.
• 🏑 Applications of differential equations are widespread in fields like economics, physics, and engineering.
• ✋ Differential equations can be linear or non-linear and can have different orders depending on the highest derivative involved.

## Transcript

Welcome to this first video, and actually the first video in the playlist on differential equations. I know I touched on this before when we did harmonic motion, and I think I might have touched on it in other subjects. But now, because of your request, we'll do a whole playlist on this. And that's a fairly useful thing, because differential equati... Read More

### Q: What is a differential equation?

A differential equation is an equation that involves an unknown function and its derivatives. It is used to describe relationships between variables and their rates of change.

### Q: What is the difference between a regular equation and a differential equation?

In a regular equation, the solution is a number or set of numbers, while in a differential equation, the solution is a function or a set of functions.

### Q: How are differential equations applied in different fields?

Differential equations have wide applications in fields like economics, physics, and engineering, where they are used to model various phenomena and understand their behavior.

### Q: How can we determine if a given function is a solution to a differential equation?

To verify if a function is a solution to a differential equation, we substitute the function and its derivatives back into the equation and check if it satisfies the equation.

## Summary & Key Takeaways

• The video introduces differential equations as equations that involve an unknown function and its derivatives.

• In contrast to regular equations, where the solution is a number or set of numbers, the solution to a differential equation is a function.

• The video demonstrates an example of a differential equation and shows how to verify if a given function is a solution to the equation.