>>13028041Dot product is simple. You're seeing the component a vector has along the direction of another vector, and multiplying the two things together.
With cosine rule and other shit, you prove that ways formula in terms of vector components.
Cross product is slightly more tricky, and you're best to look at the definition.
Where does cross product formula come from? It's actually a bit tricky, but it makes sense when you do manipulations with expressions containing the "levi-civitica". It involves the structure of cyclical permutations, and it teaches you a thing or two about the way the x, y, z axes are structured in accordance to the right hand rule. [curl your fingers from x to y, y to z, or z to x]
