How can I calculate a tangent vector at a point in 3D dimensions?

0
votes

On the z=0 plane, I have a point A(a1,b1,0). And there is another point B(a2,b2,0) which I consider it as the center of a circle. I connect AB together and then draw a circle with radius AB. There is another point C(a3,b3,c3) in the 3D zone.

How can I find the tangent vector of AC on the circle with radius AB?Ie means that I need to calculate the tangent vector of AC at point A.

1
matlabmath3dgeometryplane
Welcome to Stack Overflow! Welcome to Stackoverflow! Can you please elaborate your question having your effort like code or something so that people could get your problem early and help you? Thanks! – Enamul Hassan
Are you just looking for the vector from point A to point C? – digglemister
I need to calculate the projective tangent vector of AC on the z=0 plane. – Junyu
What is tangent vector of AC at point A? It looks nonsense. – MBo
Why should the projection of AC onto the xy plane be perpendicular to AB? This is only the case for certain points C. Anyway, what do you want to calculate? It seems that everything is already given. – Nico Schertler

1 Answers

0
votes

If you mean tangent to the circle at point A, then it is unique vector perpendicular to vector AB and is NOT dependent on any other point in 3D like point C. It should be easy to calculate.

On other hand project of AC on the plane is easy to calculate but it is NOT guaranteed to be tangent vector that you are looking for.