3.4․16 Tangents and Normals
Condition: at what points and at what angles the line \ [\ begin {array} {l} z = 4 x = 2 y \ quad {intersects} \ quad {surface} \\ x y = y+z? \ end {Array} \]
Solving Problems in Three-Dimensional Space Using Tangents and Normals, Both Straight Lines and Planes.