4123.sagews

# Figur for oppgave 10.5.17 i boka.
var('x,y,z')

# Tegn kule med radius 2.
plott1 = implicit_plot3d(x^2+y^2+z^2==4,(x,-2,2),(y,-2,2),(z,-2,2),opacity=0.4)

# Plott planet x+y+z = 1 <=> z = 1-x-y
plott2 = plot3d(1-x-y,(x,-2,2),(y,-2,2),opacity=0.6,color='red')
# Tegn punktet som er nærmest origo i planet samt origo
plott2 += point3d((1/3,1/3,1/3),size=20)
plott2 += point3d((0,0,0),size=10)

# Vis alt sammen
show(plott1+plott2,aspect_ratio=1)