Vertical and horizontal slices on a 3D surface.
Vector tangent to a 3D surface path. The vector “v” is shown representing the slope at a point along the path “c(t)”, which is determined by projection of a line in the x-y plane, onto the 3D surface, “S”.
The ‘ghosted’ grid and subtle shading helps show the “topography” of the surface in space, and there is a hierarchy and subordination of dotted and dashed constructions to help support the pedagogy, and clarify the various elements and analysis.