# Mathematics lessons

Learn the language of physics: The arts of numbers, logical definitions, and created abstract structures and their relationships to each other that will help you master physics.
Lesson
Level 1 (suitable for all)

## Set Theory: Learn Subsets, Unions, Intersections and Differences

Learn set theory in a simple way: subset, intersection, union, difference, etc. using examples and Venn diagrams.

Lesson
Level 3 (with higher mathematics)

## Differential Equations (DEQ): All the Basics Everyone Should Know

Learn what differential equations are, what types there are (ordinary, partial, linear, homogeneous), and what boundary and initial conditions are good for.

Lesson
Level 1 (suitable for all)

## The 16 most Important Geometric Objects: Overview with Formulas and Properties

Illustrated overview of all geometric solids with important properties as well as formulas for areas, volumes and other quantities.

Lesson
Level 3 (with higher mathematics)

## Gradient and How to Calculate the Directional Derivative

Learn to calculate the gradient of a function using the Nabla operator and to determine the directional derivative.

Lesson
Level 3 (with higher mathematics)

## Levi-Civita Symbol and How to Write Cross Product with it

Here you will learn about Levi-Civita symbol; how it is defined and how it can be used to write and prove scalar triple product and cross product.

Lesson
Level 3 (with higher mathematics)

## Kronecker Delta: 4 Important Rules and Scalar Product in Index Notation

Here you learn everything about Kronecker-Delta! Including 4 calculation rules with Einstein's summation convention, typical mistakes and more.