Help me find a vector parametric of the 2 intersecting surfaces.
z=9-x^2-(y-1)^2
z=2y+4
See inside for more info

Question

Help me find a vector parametric of the 2 intersecting surfaces.
z=9-x^2-(y-1)^2
z=2y+4
See inside for more info

fixxer · Answer

I have tried setting z=z $$9-x^2-(y-1)^2-2y+4=x^2+y^2-4$$

I then tried the following $$x=2\cos(t),y=2\sin(t)$$then i solved both surface equation substituting in for x and y$$z=4\sin(t)+4$$
However this is not right, the spacecurve I get is similar in shape, but the orientation is wrong

holsteremission · Answer

Really? Looks fine to me. Or do you mean orientation as in the orientation of the path (clockwise vs counerclockwise)?

fixxer · Answer

that is odd I get something completely different :s

fixxer · Answer

Wow, I had really messed up the axes for the solid. Im glad you were here to confirm the parameters, after all i picked up a few of your trick :)

holsteremission · Answer

I think you might be using $z=4-4\cos t$?

fixxer · Answer

The problem was that I plotted y values on x axis and x values on y axsis for the solid. Didnt even slip my mind before you confirmed it was the right parameters.

thanks

holsteremission · Answer

yw