Point 1 : définition vecteur normal

This lesson is about finding the direction and normal vectors of a line, and then using them to determine the equation of a perpendicular line passing through a given point. The example in the lesson shows step-by-step how to find the direction vector of a line, as well as the equation of a perpendicular line passing through a given point. The lesson emphasizes the importance of making a quick sketch to better visualize the problem being solved. By following the fundamental definitions taught in this lesson, one can find equations for lines in a straightforward manner.