Consider the implicitly defined surface 2xyz +xy +z 2 + 2 = xz2 +x+y + 2z in R 3 . (a) Find the two points of intersection of the surface with the line through the origin and in direction j + k.

Respuesta :

Answer:

The two points of intersection are:

(0, 1, 1) and (0, 2, 2)

Step-by-step explanation:

The parametric equations of the line passing through the origin (0, 0, 0) and in direction j + k is:

[tex] x=0+0t=0 [/tex] Notice x is 0t because vector j+k has no x-component  

[tex] y=0+1t=t [/tex]        

[tex]z=0+1t=t[/tex]

Then we plug them into the equation of the surface:

[tex]2xyz+xy+z^2+2=xz^2+x+y+2z[/tex]

And we get:

[tex]2(0)(t)(t)+(0)(t)+t^2+2=(0)t^2+0+t+2t[/tex]  

[tex]t^2+2=t+2t[/tex]

Collecting all term on the left side:

[tex] t^2-3t+2= 0[/tex]

Factoring:

[tex](t-2)(t-1)=0[/tex]

Solving each factor:

[tex]t=2, t=1[/tex]

Then plugging the solution into the parametric equations of the line we get:

[tex]\text{For }t=2\to x=0,y=2,z=2\\\text{For }t=1\to x=0,y=1,z=1[/tex]

So, the points of intersection are: (0, 1, 1) and (0, 2, 2)