6. (Sethian) Let C be the open curve given by x (t) = 2 sin 2t y(t) = 4 1 - cos TT t - 2 sin with 0 0, y > 0, z > 0) on the surface xy-23 = 2 that is closest to the origin. Find the equation of the plane tangent to the surface at the point P. (The numbers here are ugly, so don't panic.)