Cross product of two vectors FormulaCross Product (Definition) $$ \boldsymbol{a} ~\times~ \boldsymbol{b} ~=~ \begin{bmatrix} a_2b_3-a_3b_2 \\ a_3b_1-a_1b_3 \\ a_1b_2-a_2b_1 \end{bmatrix} $$
Formulapq-Formula (Solution of a Quadratic Equation) $$ x_1 ~=~ - \frac{\class{red}{p}}{2} ~+~ \sqrt{ \left( \frac{\class{red}{p}}{2} \right)^2 ~-~ \class{blue}{q}} $$
Example for an Intersection Set LessonLevel 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.
Point at which a Vector Field is Fivergence-Free (Source-Free) LessonLevel 3 (with higher mathematics)Divergence of a Vector Field and its Sources and Sinks Here you will learn what divergence of a vector field is and what it has to do with electric charges as sources and sinks.
Dodecahedron and its Side Length LessonLevel 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.
Parallelogram with Side Lengths and Height FormulaParallelogram (Area, Side Length) $$ A ~=~ \class{blue}{a} \, \class{red}{h} $$
Video Level 2 (without higher mathematics)Difference Between Partial and Total Derivative Here you will learn by example what the difference is between the partial derivative and the total derivative.