load(draw); xalg : -2; xlopp : 4; yalg : -1; ylopp : 5; draw3d(xu_grid=50,yv_grid=50,xlabel="x",ylabel="y",zlabel="z", explicit(2*x**2 + y**2, x,xalg,xlopp, y,yalg,ylopp), color=red,line_width=3,parametric(x, 2, 2*x**2+4, x,xalg,xlopp), line_width=1,parametric(x, 2, 4*x+2, x,xalg,xlopp), color=black,line_width=3,parametric(1, y, 2+y**2, y,yalg,ylopp), line_width=1,parametric(1, y, 4*y-2, y,yalg,ylopp),zrange=[0,20]); xalg : -3; xlopp : 5; yalg : -2; ylopp : 6; tasand(x,y) := 4*x + 4*y - 6; h1 : 1; h2 : 2; draw3d(xu_grid=50,yv_grid=50,xlabel="x",ylabel="y",zlabel="z", color=green, explicit(tasand(x,y), x,xalg,xlopp,y,yalg,ylopp), color=blue, explicit(2*x**2 + y**2, x,xalg,xlopp, y,yalg,ylopp), color=red,line_width=3,parametric(x, 2, 2*x**2+4, x,xalg,xlopp), line_width=1,parametric(x, 2, 4*x+2, x,xalg,xlopp), color=black,line_width=3,parametric(1, y, 2+y**2, y,yalg,ylopp), line_width=1,parametric(1, y, 4*y-2, y,yalg,ylopp), color=brown, line_width=1, parametric(1+t*h1, 2+t*h2, 6, t,0,3), parametric(1, 2+t*h2, 6, t,0,1), parametric(1+t*h1, 2, 6, t,0,1), parametric(1+h1, 2+t*h2, 6, t,0,1), parametric(1+t*h1, 2+h2, 6, t,0,1), parametric(1+t*h1, 2+t*h2, tasand(1+t*h1,2+t*h2), t,0,3), line_width=5, parametric(1+h1, 2+h2, z, z,min(6,tasand(1+h1,2+h2)),max(6,tasand(1+h1,2+h2))), color=pink,line_width=5, parametric(1+h1, 2+h2, z, z,min(2*(1+h1)**2+(2+h2)**2,tasand(1+h1,2+h2)),max(2*(1+h1)**2+(2+h2)**2,tasand(1+h1,2+h2))), color=black, label(["df", 1+h1+0.2, 2+h2+0.2, (6+tasand(1+h1,2+h2))/2]), label(["dx", 1+h1/2, 2+0.2, 6]), label(["dy", 1+0.2, 2+h2/2, 6]), label(["{/Symbol a}", 1+h1+0.2, 2+h2+0.2, (2*(1+h1)**2+(2+h2)**2+tasand(1+h1,2+h2))/2]), zrange=[0,30],xrange=[xalg,xlopp],yrange=[yalg,ylopp],xyplane=0); xalg : -1; xlopp : 3; yalg : 0; ylopp : 4; draw3d(xu_grid=50,yv_grid=50,xlabel="x",ylabel="y",zlabel="z", explicit(x**3-2*x**2*y+x*y**2+1, x,xalg,xlopp, y,yalg,ylopp), color=red,line_width=3,parametric(1+3*t, 2+4*t, (1+3*t)**3-2*(1+3*t)**2*(2+4*t)+(1+3*t)*(2+4*t)**2+1, t,-3,3), line_width=1,parametric(1+3*t, 2+4*t, -1*(1+3*t)+2*(2+4*t) -1, t,-3,3), zrange=[0,10],xrange=[xalg,xlopp],yrange=[yalg,ylopp]);