“…The tangent vector fields of the surface M 2 are X u = 5u 4 , 1, 0, 0, 4u 3 , 3u 2 , X v = 0, 0, 1, 2v, 0, 0 . Then, since {X u , X v , e 1 , e 5 , e 6 } is linearly independent, we obtain the basis vectors of the normal space of M 2 as [11] N 4 , 0, 0, 320u 13 + 20u 7 , 240u 12 + 15u 6 . Also, we have…”