3332.sagews

Evalute the first partial derivatives of the given function at the point (1,2,1)

#auto
x, y, z, t = var('x, y, z, t')
f(x,y)=1-(x-1)^2-(y-2)^2
P=plot3d(f, (x,-5, 5), (y,-5, 5), color='red')
Q=implicit_plot3d(x==1, (x,-5,5), (y,-5,5), (z,-26,168))
R=parametric_plot3d((1, t, -t^2+4*t-3), (t, -5, 5), color='black', thickness=10)
S=point3d((1,2,1),size=40,color='black')
show(P+Q+R+S,figsize=(6,6))