Matlab tutorial playing with points, vectors, parametric equations and planes in 3 space 

I do not know much more about using meshgrid than that in video.

Learned matlab for applied linear algebra. Very nice when you get to know it and very intuitive. Try turning image with mouse.

It is the magnitude of vector. Pythagorean theorem. Vector divided by its magnitude is a unit vector whose norm is equal to 1. Just point in the direction of the vector like i,j and k points in x,y and z direction.

@@jeanjoubert8071 can i ask more, when sir put v1x = xt; yt; zt+4; why there is +4 in zt

@@Raven_Ray1 I will have to go look. It is parametric equations for lines in 3d

The xt is from the vector that you get from subrtacting the points (slope) and the you add the point coordinates for height. For p x and y = 0 and z = 4

@@jeanjoubert8071 thank you very much sir.