Hi, I'm programming a visual implimentation of a bezier curve for a coursework. It would be beneficial for me to find the tangent at any point t on the curve. I can calculate the position of a point t, and so can hash the problem somewhat by finding the gradient between t+- a small value, but I was hoping for a more mathmatically accurate method. So I have the basic equation nCr * t^r * (1-t)^(n-r) * Vector for point which I tried to differentiate to... nCr * r * t^(r-1) * -(n-r) * (1-t) * Vector for point where t is progress along curve (between 0 and 1) n is the number of control points r is which iteration of the list of points we're on. is this correct? I'm not sure if it's the programming or the maths that are causing the problem.