var('r,s')
paraboloid = parametric_plot3d((r*cos(s),r*sin(s),r^2),(r,0,1.8),(s,0,2*pi),color='green')
ellipsoid = parametric_plot3d((3/2*sin(r)*cos(s),3*sin(r)*sin(s),3*cos(r)),\
(r,0,pi),(s,0,2*pi),color='purple',opacity=.5)
point = point3d((-1,1,2),size=7.5,color='black')
tanline = parametric_plot3d((-1-5*s,1-8*s,2-6*s),(s,-0.2,0.16),color='black')
(paraboloid + ellipsoid + point + tanline).show(aspect_ratio=[1,1,1])
