04作x3-3xy' fy(x, y] = D[f(x, y], y] ЗУ (x, y}, Reals] raot: Solve [f, [x, y] =0 && fy[x, y] = 0, 0])))) 0, f[0, Point1= Graphics3D [(PointSize [.05], Point [ { 0, rail:
Point! = Graphics 3D [ { PointSise [-05] , Point [ {0 , 0 , f [0 , 0 ] } ] } ] rail: surfce1= ContourPlot3D [f(x, y], {x, -5, 5), {y, -5, 5), {s, -5, 5), Contours→(-2, -1, 0, 1, 2, 3.5)) ra꺄
n33- Show [surfcel, Pointl] axes backgroundr E remove bounding box more...