Find a vector tangent to the space circle:

At the point

I should know how to do this, but it's been 4 years since I had multivariable calc and I don't remember a darn thing from that class. :-(

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- Jan 14th 2011, 12:49 PMmathematicalbagpiperTangent Vector to a Space Circle
Find a vector tangent to the space circle:

At the point

I should know how to do this, but it's been 4 years since I had multivariable calc and I don't remember a darn thing from that class. :-( - Jan 14th 2011, 01:39 PMemakarov
Since the circle belongs to the plane x + y + z = 0, the tangent vector belongs to it as well. Also, the vector is perpendicular to the radius-vector . So you have two equations: x + y + z = 0 and x + 2y - 3z = 0. I get (-5, 4, 1) up to proportionality.

- Jan 14th 2011, 01:49 PMzzzoak

The normal vector to the tangent plane to the sphere is .

The normal vector of the given plane is p=(1,1,1).

The vector perpendicular to and is (cross product)