This is the best explanation of the projection formula that I have ever seen. Prof. Strang not only provides a mathematical basis of the formula by deriving it, but also provides clear intuition and motivation. He also takes the time to go through the simpler case of projecting onto a line first, which allows building up the understanding of the content gradually. What a great lecture!####[['Prof. Strang', 'Instructor', 'POS'], ['explanation', 'Mathematical_Related_Concept', 'POS']]