Question

What is the vector projection formula?

Answer 1

If we have two vectors A and B with an angle `theta` between them when they are joined tail to tail ( To remove ambiguity, `theta < pi`), then the projection of either vector (say, B) in the direction of A is the component of B along A and is given by, B `Cos theta`.
Similarly, projection of A in the direction of B is A `Cos theta` .