Surfaces in Space / Vector-Valued Functions

llauren84
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Homework Statement



Sketch the space curve represented by the intersection of the surfaces. Then represent the curve by a vector-valued function.


Homework Equations



Surfaces: z=x2+y2, x+y=0
Parameter: x=t


The Attempt at a Solution



So, I sketched the space curve represented by the intersection of the two curves. It's simply a parabola. However, I can't seem to think of how to put it into a vector-valued function. I'm getting a mind block. (Perhaps, before anyone answers this, I may come up with the answer.)
 
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Got it yet? You already have x=t. What's y in terms of t? (Put x=t into the plane equation). Finally z=?
 
So, it's just z=t2+(-t)2? and..no I didn't get it yet. I put down my math and did other things. Thanks =) So, it's r(t)=<t,-t,2t2>?
 
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Yes, that's z.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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