Todd Casey 122 Report post Posted June 16, 2000 What is a tangent vector and how would I calculate such a vector? Thanks for any information. Todd 0 Share this post Link to post Share on other sites

ga 126 Report post Posted June 16, 2000 A tangent vector of a curve is a vector which starts at one point of the curve and has the same direction as the curve at this point. If you''ve got a parametrized curve in 3D space, curve(t) = (x(t),y(t),z(t)), you get the tangent vector if you derive x(t), y(t) and z(t): tangent vector(t) = (dx(t)/dt,dy(t)/dt,dz(t)/dt). Visit our homepage: www.rarebyte.de.stGA 0 Share this post Link to post Share on other sites

Todd Casey 122 Report post Posted June 16, 2000 Thanks for the explanation!Todd 0 Share this post Link to post Share on other sites

OldManDave 122 Report post Posted June 16, 2000 Hey, Yeah, you''d need to know calculus for that. Or if you give the equation of the curve, maybe someone here (including me) could give you the differentiated equation. Basically, you take the equation of the curve/line, find the derivative, and evaluate the derivative at the point of tangency. This is the direction of the vector (actually its the slope of any line, but... here it could be considered the direction). Now the magnitutde of the vector is what you''d need to have. A true tangent vector doesn''t need a specific magnitude... I think a unit vector would do fine as a tangent.Hope this helps, but give the equation of a curve so we could better help you.OldManDave. 0 Share this post Link to post Share on other sites

Mezz 571 Report post Posted June 16, 2000 doesn''t deriving just give you the gradient?Although I suppose you you could work out the rest from that...-Mezz 0 Share this post Link to post Share on other sites

ga 126 Report post Posted June 18, 2000 quote:Original post by Mezz doesn''t deriving just give you the gradient?Although I suppose you you could work out the rest from that...-Mezz I think the gradient is the derivation of a scalar function with more than one parameter, e.g. f(x,y,z) gives a scalar value, e.g. f(x,y,z) = sqrt(x^2 + y^2 + z^2) for the length of a vector. Then the gradient is(df(x,y,z)/dx, df(x,y,z)/dy,df(x,y,z)/dz)It gives us the direction in whích the value of the scalar function has the biggest change. Visit our homepage: www.rarebyte.de.stGA 0 Share this post Link to post Share on other sites