Visualizing a Parametric Equation in 3D Space

CourtneyS
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Homework Statement


Given the eqn x=2, y=sin(t), z=cos(t), draw this function in 3-space.

Homework Equations


ABOVE^

The Attempt at a Solution


I did this:
x^2+y^2+z^2=2^2+(sin(t))^2+(cos(t))^2=5
Therefore we get x^2+y^2+z^2=5
Which is the eqn of a sphere with radius root5.

My friend said it's supposed to be a circle but I can't see how?
Which one of us is right if either.
 
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If x is always equal to 2, how can it be a sphere?
 
phyzguy said:
If x is always equal to 2, how can it be a sphere?
:(
 
CourtneyS said:
:(
Another way of looking at it... there is only one degree of freedom (t), so it must be a line, not a surface.
 
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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